Devry MATH221 All Quizzes Latest 2021 June

MATH221 Statistics for Decision Making

Week 1 Quiz

Question 1(CO 1) Among 500 people at the concert, a survey of 35 found 28% found it too loud. What is the population and what is the sample?

  Population: 500 at that concert; Sample: the 28% who found it too loud

  Population: all concert goers; Sample: the 28% who found it too loud

  Population: 500 at that concert; Sample: the 35 in the survey

  Population: all concert goers; Sample: the 500 at that concert

 Question 2(CO 1) In asking all 349 second graders in a school district, it is found that on average, these second graders have 2.5 pets. Is this number a parameter or a statistic and why?

  Parameter as it represents the population

  Statistic as it represents the sample

  Parameter as it represents the sample

  Statistic as it represents the population

 Question 3(CO 1) Classify the data of the top grossing movies for 2017.

  Classical

  Qualitative

  Quantitative

  Statistics

 Question 4(CO 1) The data set that lists a company’s competitors and their locations would be classified as what type of data?

  Ordinal

  Nominal

  Ratio

  Interval

 Question 5(CO 1) A data set that includes the shows on a station during the day would be classified as what type of data?

  Ratio

  Interval

  Ordinal

  Nominal

 

 

MATH221 Statistics for Decision Making

Week 2 Quiz

Question 1(CO 2) A random number generator is used to select a number from 1 to 100. What is the probability of selecting an odd number?

  0.077

  0.500

  0.050

  0.250

 Question 2(CO 2) What is the sample space of flipping three coins, where H=heads, and T=tails?

  (H,H,H)(H,H,H)(H,H,H)(H,H,H)(T,T,T)(T,T,T)(T,T,T)(T,T,T)

  (H,H,H)(H,H,T)(H,T,T)(T,H,H)(T,T,H)(T,T,T)(T,H,T)(H,T,H)

  (H,H,T)(H,T,T)(T,H,H)(T,T,H)(T,T,T)(T,H,T)(H,T,H)

  (H,H,H)(T,T,T)

 Question 3(CO 2) Consider the table below

Response (number of cats owned)          Frequency

None     659

One       329

Two       52

Three    13

Four or more     8

What is the probability that the next person asked has only one cat?

  50%

  31%

  5%

  62%

 Question 4(CO 2) Consider the table below

Age Group          Frequency

18-29     9831

30-39     7845

40-49     6869

50-59     6323

60-69     5410

70 and over        5279

What is the probability that the next person chosen will be in the 18-29 or 30-39 age groups?

  42.5%

  37.8%

  23.7%

  18.9%

 Question 5(CO 2) Based on the CEO’s perception, a company estimates that a new product will be purchased by 32% of current customers. This is an example of which type of probability?

  Empirical probability

  Subjective probability

  Public probability

  Classical probability

 

MATH221 Statistics for Decision Making

Week 3 Quiz

Question 1(CO 3) Consider the following table:

Age Group          Frequency

18-29     983

30-39     784

40-49     686

50-59     632

60-69     541

70 and over        527

If you created the probability distribution for these data, what would be the probability of 40-49?

  0.189

  0.165

  0.425

  0.237

 Question 2(CO 3) Consider the following table of hours worked by part-time employees. These employees must work in 5 hour blocks.

Weekly hours worked   Probability

5              0.06

15           0.18

20           0.61

25           0.15

Find the mean of this variable.

  2.70

  12.20

  0.61

  18.95

 Question 3(CO 3) Consider the following table.

Defects in batch               Probability

0              0.30

1              0.28

2              0.21

3              0.09

4              0.08

5              0.04

Find the variance of this variable.

  1.41

  0.67

  1.49

  1.99

 Question 4(CO 3) Consider the following table:

Defects in batch               Probability

0              0.04

1              0.11

2              0.25

3              0.20

4              0.19

5              0.21

Find the standard deviation of this variable.

  2.08

  1.41

  3.02

  1.44

 Question 5(CO 3) Fifty-four percent of US teens have heard of a fax machine. You randomly select 12 US teens. Find the probability that the number of these selected teens that have heard of a fax machine is exactly six (first answer listed below). Find the probability that the number is more than 8 (second answer listed below).

  0.217, 0.120

  0.284, 0.120

  0.284, 0.160

  0.217, 0.280

 

MATH221 Statistics for Decision Making

Week 4 Quiz

Question 1 (CO 3) The speed of cars on a stretch of road is normally distributed with an average 42 miles per hour with a standard deviation of 5.9 miles per hour. What is the probability that a randomly selected car is violating the speed limit of 50 miles per hour?

  0.21

  0.91

  0.09

  0.59

 Question 2(CO 3) A survey indicates that shoppers spend an average of 22 minutes with a standard deviation of 8 minutes in your store and that these times are normally distributed. Find the probability that a randomly selected shopper will spend less than 20 minutes in the store.

  0.22

  0.40

  0.60

  0.50

 Question 3(CO 3) The monthly utility bills in a city are normally distributed with a mean of $128 and a standard deviation of $23. Find the probability that a randomly selected utility bill is between $110 and $130.

  0.783

  0.316

  0.318

  0.217

 Question 4(CO 3) A restaurant serves hot chocolate that has a mean temperature of 175 degrees with a standard deviation of 8.1 degrees. Find the probability that a randomly selected cup of hot chocolate would have a temperature of less than 164 degrees. Would this outcome warrant a replacement cup (meaning that it would be unusual)?

  Probability of 0.91 and would warrant a refund

  Probability of 0.91 and would not warrant a refund

  Probability of 0.09 and would not warrant a refund

  Probability of 0.09 and would warrant a refund

 Question 5(CO 3) The yearly amounts of carbon emissions from cars in Belgium are normally distributed with a mean of 13.9 gigagrams per year and a standard deviation of 9.2 gigagrams per year. Find the probability that the amount of carbon emissions from cars in Belgium for a randomly selected year are between 11.5 gigagrams and 14.0 gigagrams per year.

  0.107

  0.397

  0.603

  0.496

 

MATH221 Statistics for Decision Making

Week 5 Quiz

Question 1(CO 4) From a random sample of 55 businesses, it is found that the mean time that employees spend on personal issues each week is 4.9 hours with a standard deviation of 0.35 hours. What is the 95% confidence interval for the amount of time spent on personal issues?

  (4.82, 4.98)

  (4.83, 4.97)

  (4.84, 4.96)

  (4.81, 4.99)

 Question 2(CO 4) If a confidence interval is given from 8.56 to 10.19 and the mean is known to be 9.375, what is the maximum error?

  0.408

  1.630

  0.815

  8.560 

Question 3(CO 4) Which of the following is most likely to lead to a large margin of error?

  small sample size

  large sample size

  small standard deviation

  small mean

 Question 4(CO 4) From a random sample of 85 teens, it is found that on average they spend 31.8 hours each week online with a population standard deviation of 5.91 hours. What is the 90% confidence interval for the amount of time they spend online each week?

  (25.89, 37.71)

  (30.75, 32.85)

  (30.62, 32.99)

  (19.98, 43.62)

 Question 5(CO 4) A company making refrigerators strives for the internal temperature to have a mean of 37.5 degrees with a standard deviation of 0.6 degrees, based on samples of 100. A sample of 100 refrigerators have an average temperature of 37.53 degrees. Are the refrigerators within the 90% confidence interval?

  Yes, the temperature is within the confidence interval of (36.90, 38.10)

  No, the temperature is outside the confidence interval of (36.90, 38.10)

  No, the temperature is outside the confidence interval of (37.40, 37.60)

  Yes, the temperature is within the confidence interval of (37.40, 37.60)

 

MATH221 Statistics for Decision Making

Week 6 Quiz

Question 1(CO 5) A company claims that its heaters last less than 5 years. Write the null and alternative hypotheses and note which is the claim.

  Ho: μ ≥ 5, Ha: μ < 5 (claim)

  Ho: μ > 5 (claim), Ha: μ ≤ 5

  Ho: μ ≤ 5, Ha: μ > 5 (claim)

  Ho: μ = 5 (claim), Ha: μ ≥ 5

Question 2(CO 5) An executive claims that her employees spend no more than 2.5 hours each week in meetings. Write the null and alternative hypotheses and note which is the claim.

  Ho: μ ≤ 2.5, Ha: μ < 2.5 (claim)

  Ho: μ ≤ 2.5 (claim), Ha: μ > 2.5

  Ho: μ > 2.5, Ha: μ ≤ 2.5 (claim)

  Ho: μ = 2.5 (claim), Ha: μ ≥ 2.5

Question 3(CO 5) In hypothesis testing, a key element in the structure of the hypotheses is that the math tests the support for the ________________________.

  claim

  the truth

  alternative hypothesis

  null hypothesis

Question 4(CO 5) A landscaping company claims that at most 90% of workers arrive on time. If a hypothesis test is performed that rejects the null hypothesis, how would this decision be interpreted?

  There is not sufficient evidence to support the claim that at least 90% of workers arrive on time

  There is sufficient evidence to support the claim that a least 90% of workers arrive on time

  There is sufficient evidence to support the claim that at most 90% of workers arrive on time

  There is not sufficient evidence to support the claim that at most 90% of workers arrive on time

Question 5(CO 5) A textbook company claims that their book is so engaging that less than 55% of students read it. If a hypothesis test is performed that rejects the null hypothesis, how would this decision be interpreted?

  There is not sufficient evidence to support the claim that no more than 55% of students read this text

  There is not sufficient evidence to support the claim that less than 55% of students read this text

  There is sufficient evidence to support the claim that less than 55% of students read this text

  There is sufficient evidence to support the claim that no more than 55% of students read this text

 

MATH221 Statistics for Decision Making

Week 7 Quiz

Question 1(CO 6) The coefficient of determination is represented by what notation?

  r

  β

  ρ

  r2

Question 2(CO 6) Two variables have a negative linear correlation. Does the independent variable increase or decrease as the dependent variable increases?

  Independent variable decrease

  Independent variable would remain the same

  Cannot determine from information given

  Independent variable increases

Question 3(CO 6) Find the regression equation for the following data set

x          245       287       198       189       176       266       210       155

y          50         80        110      78        44        57        51        44

  ? = 45.69x – 0.69

  ? = 0.09x + 45.69

  ? = 45.69x + 0.09

  cannot be determined

Question 4(CO 6) A student wants to determine if a higher quality diet will improve their grade point average. Which variable would be the response variable?

  The student

  Their GPA

  The higher quality diet

  The number of classes taken

Question 5(CO 6) A value of the slope of the regression line would be given the notation of:

  m

  r

  r2

  b

 

MATH221 Statistics for Decision Making

Week 8 Quiz

Question 1If neighbors wanted to have a speed bump installed on one part of the road, which statistical method would be most effective.

  Regression with speed as the dependent variable

  Hypothesis testing with a null hypothesis that the speed is less than or equal to the posted speed

  Hypothesis testing with a null hypothesis that the speed is more than the posted speed

  Use a confidence interval with the posted speed as the mean

  Regression with speed as an independent variable

 Question 2If a franchise company wanted to determine why sales were higher at some locations rather than others, what statistical process would be most appropriate?

  Use a confidence interval with the posted speed as the mean

  Regression with sales as the dependent variable

  Hypothesis testing with a null hypothesis that the sales are less than or equal to the highest sales

  Regression with sales as an independent variable

  Hypothesis testing with a null hypothesis that the sales are more than the highest sales

 Question 3A coffee shop fills its 10 fluid ounce cups, but tries to come up a bit short so that customers don’t spill hot coffee on themselves.  The cups are sold as having 9.5 fluid ounces.  What statistical strategy would allow them to see if this method is being implemented correctly?

  A hypothesis test with an alternative hypothesis that is less than 10 fluid ounces

  A hypothesis test with an alternative hypothesis that is less than 9.5 fluid ounces

  A confidence interval with 10 fluid ounces as the mean

  A hypothesis test with an alternative hypothesis that is more than 9.5 fluid ounces

  A hypothesis test with an alternative hypothesis that is more than 10 fluid ounces

 Question 4A teacher wants to track the number of books students have read each week, encouraging them to increase their reading throughout the school year.  Which of the following graphs might be most effective to inspire the student?

  A week-by-week pie chart

  A new scatter plot each week with each student on the x axis and number of books on the y axis

  A time series graph with the weeks on the x axis and number of books on the y axis

  A time series graph with each student on the x axis and attendance on the y axis

  A Pareto chart showing the week with the most books read to the week with the least books read

 Question 5A TV reporter is looking at polling for the coming presidential election. He wants to determine if the polling shows that one candidate or the other has a true lead on the other candidate.  Which statistical method would help determine if one candidate has a true lead in the election?

  Find a confidence interval for each candidate’s poll results and check that they do not overlap

  Regression with poll results as the independent variable

  Use a confidence interval based on last year's polling results

  Regression with poll results as the dependent variable

  Compare the sample mean of each