# Statistics Quiz

Question 1 of 20

1.0 Points

The form of the alternative hypothesis can be:

A.one-tailed

B.two-tailed

C.neither one nor two-tailed

D.one or two-tailed

Question 2 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. = 30.58

B.= 27.50

C.t = 27.50

D.z = 1.65

Question 3 of 20

1.0 Points

A two-tailed test is one where:

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

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

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

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

Question 4 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

Question 5 of 20

1.0 Points

A severe storm has an average peak wave height of 16.4 feet for waves hitting the shore. Suppose that a storm is in progress with a severe storm class rating. Let us say that we want to set up a statistical test to see if the wave action (i.e., height) is dying down or getting worse. If you wanted to test the hypothesis that the waves are dying down, what would you use for the alternate hypothesis? Is the P-value area on the left, right, or on both sides of the mean?

A.H1: is greater than 16.4 feet; the P-value area is on both sides of the mean

B.H1: is less than 16.4 feet; the P-value area is on the left of the mean

C.H1: is not equal to 16.4 feet; the P-value area is on the right of the mean

D.H1: is greater than 16.4 feet; the P-value area is on the left of the mean

Question 6 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 a = .05 level of significance, does the nutritionist have enough evidence to reject the writer’s claim?

A.No

B.Yes

C.Cannot Determine

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.

Compute the z or t value of the sample test statistic.

A.z = 1.96

B.z = 0.62

C.t = 1.645

D.z = 0.69

Question 8 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: p ≤ .79, H1: p > .79

B.H0: p = .79, H1: p ≠ .79

C.

H0: = .79, H1: > .79

D.H0: m = .79, H1: m > .79

Question 9 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.

State the null and alternative hypotheses.

A.H0: 75, H1: > 75

B.H0: 75, H1: < 75

C.H0: = 75, H1: > 75

D.H0: = 75, H1: ≠ 75

Question 10 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?

State the null and alternative hypotheses.

A.H0: s2 ≤ 1.2, H1: s2 > 1.2

B.H0: s2 ≥ 1.2, H1: s2 ≠ 1.2

C.H0: s2 < 1.2, H1: s2 ≠ 1.2

D.H0: s2 ≠ 1.2, H1: s2 = 1.2

Question 11 of 20

1.0 Points

The hypothesis that an analyst is trying to prove is called the:

A.level of significance

B.elective hypothesis

C.alternative hypothesis

D.quality of the researcher

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.

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 30 firemen and found s = 27.2 pounds.

Assuming that the weights of firemen are normally distributed, if the statistician wanted to test her research hypothesis at the .05 level of significance, what is the critical value?

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

Suppose a firm that produces light bulbs wants to know whether it can say that its light bulbs typically last more than 1500 hours. Hoping to find support for their claim, the firm collects a random sample of n = 25 light bulbs and records the lifetime (in hours) of each bulb. The information related to the hypothesis test is presented below.

Test of H0: 1500 versus H1: > 1500

Sample mean 1509.5

Std error of mean 4.854

Assuming the life length of this type of lightbulb is normally distributed, what is the p-value associated with this test? Place your answer, rounded to 3 decimal places in the blank. For example, .123 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.

Compute the test value that you would use in conducting this test. Place your answer, rounded to 3 decimal places, in the blank. For example, -2.345 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.

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, the doctor would perform a chi-square test to test her research hypothesis. In that case, what is the test value that she would compute.

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

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.

Suppose a firm that produces light bulbs wants to know whether it can say that its light bulbs typically last more than 1500 hours. Hoping to find support for their claim, the firm collects a random sample of n = 25 light bulbs and records the lifetime (in hours) of each bulb. The information related to the hypothesis test is presented below.

Test of H0: 1500 versus H1: > 1500

Sample mean 1509.5

Std error of mean 4.854

Assuming the life length of this type of lightbulb 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 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 survey determines that mint chocolate chip is the favorite ice cream flavor of 6% of consumers. An ice cream shop determines that of 260 customers, 20 customers stated their preference for mint chocolate chip.

Find the P-value that would be used to determine if the percentage of customers who prefer mint chocolate chip ice has increased at a 5% level of significance.

P-value: Round your answer to four decimal places as necessary.

Part 3 of 3 –

Question 18 of 20

1.0 Points

If a null hypothesis about a population mean is rejected at the 0.025 level of significance, then it must also be rejected at the 0.01 level.

True

False

Question 19 of 20

1.0 Points

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

True

False

Question 20 of 20

1.0 Points

Sample evidence is statistically significant at the level only if the p–value is larger than .

True

False