Statistics Questions

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Question 1 of 20 1.0 Points

A lab technician is tested for her consistency by taking multiple measurements of

cholesterol levels from the same blood sample. The target accuracy is a variance in

measurements of 1.2 or less. If the lab technician takes 16 measurements and the

variance of the measurements in the sample is 2.2, does this provide enough evidence

to reject the claim that the lab technician’s accuracy is within the target accuracy?

Compute the value of the appropriate test statistic.

A.t = 27.50

B. = 27.50

C.z = 1.65

D. = 30.58

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Question 2 of 20 1.0 Points

A two-tailed test is one where:

A.results in only one direction can lead to rejection of the null hypothesis

B.results in either of two directions can lead to rejection of the null hypothesis

C.no results lead to the rejection of the null hypothesis

D.negative sample means lead to rejection of the null hypothesis

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Question 3 of 20 1.0 Points

In an article appearing in Today’s Health a writer states that the average number of calories in a serving

of popcorn is 75. To determine if the average number of calories in a serving of popcorn is different from

75, a nutritionist selected a random sample of 20 servings of popcorn and computed the sample mean

number of calories per serving to be 78 with a sample standard deviation of 7.

At the  = .05 level of significance, does the nutritionist have enough evidence to reject the

writer’s claim?

A.Cannot Determine

B.No

C.Yes

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Question 4 of 20 1.0 Points

The “Pizza Hot” manager commits a Type I error if he/she is

A.staying with old style when new style is better

B.switching to new style when it is better than old style

C.staying with old style when new style is no better than old style

D.switching to new style when it is no better than old style

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Question 5 of 20 1.0 Points

A lab technician is tested for her consistency by taking multiple measurements of

cholesterol levels from the same blood sample. The target accuracy is a variance in

measurements of 1.2 or less. If the lab technician takes 16 measurements and the

variance of the measurements in the sample is 2.2, does this provide enough evidence

to reject the claim that the lab technician’s accuracy is within the target accuracy?

At the  = .01 level of significance, what is your conclusion?

A.Do not reject H0. At the = .01 level of significance there is not sufficient

evidence to suggest that this technician’s true variance is greater than the target

accuracy.

B.Reject H0. At the = .01 level of significance, there is enough evidence to support the claim

that this technician’s variance is larger than the target accuracy.

C.

Reject H0. At the = .01 level of significance, there is not enough evidence to support the claim that

this technician’s true variance is larger than the target accuracy.

D.Cannot determine

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Question 6 of 20 1.0 Points

The alternative hypothesis is also known as the:

A.optional hypothesis

B.null hypothesis

C.research hypothesis

D.elective hypothesis

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Question 7 of 20 1.0 Points

Results from previous studies showed 79% of all high school seniors from a certain city plan to attend

college after graduation. A random sample of 200 high school seniors from this city reveals that 162 plan

to attend college. Does this indicate that the percentage has increased from that of previous studies?

Test at the 5% level of significance.

State the null and alternative hypotheses.

A.

H0: = .79, H1: > .79

B.H0:  = .79, H1:  > .79

C.H0: p ≤ .79, H1: p > .79

D.H0: p = .79, H1: p ≠ .79

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Question 8 of 20 1.0 Points

The null and alternative hypotheses divide all possibilities into:

A.two sets that overlap

B.two sets that may or may not overlap

C.two non-overlapping sets

D.as many sets as necessary to cover all possibilities

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Question 9 of 20 1.0 Points

A null hypothesis can only be rejected at the 5% significance level if and only if:

A.the null hypotheses includes sampling error

B.the null hypothesis is biased

C.a 95% confidence interval does not include the hypothesized value of the parameter

D.a 95% confidence interval includes the hypothesized value of the parameter

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Question 10 of 20 1.0 Points

Results from previous studies showed 79% of all high school seniors from a certain city

plan to attend college after graduation. A random sample of 200 high school seniors

from this city reveals that 162 plan to attend college. Does this indicate that the

percentage has increased from that of previous studies? Test at the 5% level of

significance.

What is the p-value associated with your test of hypothesis?

A.0.7563

B.0.4874

C.0.6874

D.0.2437

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Question 11 of 20 1.0 Points

Results from previous studies showed 79% of all high school seniors from a certain city

plan to attend college after graduation. A random sample of 200 high school seniors

from this city reveals that 162 plan to attend college. Does this indicate that the

percentage has increased from that of previous studies? Test at the 5% level of

significance.

What is your conclusion?

A.Do not reject H0. There is not enough evidence to support the claim that the proportion of

students planning to go to college is greater than .79.

B.Reject H0. There is enough evidence to support the claim that the proportion of students

planning to go to college is now greater than .79.

C.More seniors are going to college

D.Cannot determine

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Part 2 of 3 -

Question 12 of 20 1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces

(e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific

notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

The ABC battery company claims that their batteries last at least 100 hours, on average. Your

experience with their batteries has been somewhat different, so you decide to conduct a test to see if the

company's claim is true. You believe that the mean life is actually less than the 100 hours the company

claims. You decide to collect data on the average battery life (in hours) of a random sample of n = 20

batteries. Some of the information related to the hypothesis test is presented below.

Test of H0: 100 versus H1: 100

Sample mean 98.5

Std error of mean 0.777

Assuming the life length of batteries is normally distributed, if you wish to conduct this test using a .05

level of significance, what is the critical value that you should use? Place your answer, rounded to 3

decimal places in the blank. For example, -1.234 would be a legitimate entry.

Question 13 of 20 1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces

(e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific

notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

The ABC battery company claims that their batteries last 100 hours, on average. You decide to conduct a

test to see if the company's claim is true. You believe that the mean life may be different from the 100

hours the company claims. You decide to collect data on the average battery life (in hours) of a random

sample of n = 20 batteries. Some of the information related to the hypothesis test is presented below.

Test of H0: = 100 versus H1: 100

Sample mean 98.5

Std error of mean 0.777

Assuming the life length of batteries is normally distributed, if you wish to conduct this test at the 0.05

level of significance, what are the critical values that you should use? Place the smaller critical value,

rounded to 3 decimal places, in the first blank. For example, -1.234 would be a legitimate entry.

. Place the larger critical value, rounded to 3 decimal places, in the second blank. For

example, 1.234 would be a legitimate entry.

Question 14 of 20 1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces

(e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific

notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

The CEO of a software company is committed to expanding the proportion of highly qualified women in

the organization’s staff of salespersons. He believes that the proportion of women in similar sales

positions across the country is less than 45%. Hoping to find support for his belief, he directs you to test

H0: p .45 vs H1: p < .45.

In doing so, you collect a random sample of 50 salespersons employed by his company, which is thought

to be representative of sales staffs of competing organizations in the industry. The collected random

sample of size 50 showed that only 18 were women.

What is the smallest level of significance at which you could reject the null in favor of the alternative

hypothesis? Place your answer, rounded to 4 decimal places, in the blank. For example, 0.1234 would be

a legitimate entry.

Question 15 of 20 1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces

(e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific

notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

At a university, the average cost of books per student has been $550 per student per semester. The

Dean of Students believes that the costs are increasing and that the average is now greater than $550.

He surveys a sample of 40 students and finds that for the most recent semester their average cost was

$630 with a standard deviation of $120. What is the test value for this hypothesis test?

Test value: Round your answer to two decimal places as necessary.

Question 16 of 20 1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces

(e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific

notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

A statistician wishes to test the claim that the standard deviation of the weights of firemen is greater than

25 pounds. To do so, she selected a random sample of 20 firemen and found s = 27.2 pounds.

Assuming that the weights of firemen are normally distributed, to test her research hypothesis the

statistician would use a chi-square test. In that case, what is the computed test value?

Place your answer, rounded to 3 decimal places, in the blank. For example, 23.456 would be a legitimate

entry.

Question 17 of 20 1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces

(e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific

notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

A medical doctor wishes to test the claim that the standard deviation of the systolic blood pressure of

deep sea divers is greater than 450. To do so, she selected a random sample of 25 divers and found s =

468.

Assuming that the systolic blood pressures of deep sea divers are normally distributed, if the doctor

wanted to test her research hypothesis at the .01 level of significance, what is the critical value?

Place your answer, rounded to 3 decimal places, in the blank. For example, 34.567 would be a legitimate

entry.

Part 3 of 3 -

Question 18 of 20 1.0 Points

A low p–value provides evidence for accepting the null hypothesis and rejecting the alternative.

True

False

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Question 19 of 20 1.0 Points

The smaller the p–value, the more evidence there is in favor of the alternative hypothesis.

True

False

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Question 20 of 20 1.0 Points

In order to determine the p-value, it is unnecessary to know the level of significance.

True

False