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?
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
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