Statistics Quiz 3
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It is a timed quiz so work must be done within 1 hour.
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Question 1 of 20 1.0 Points
A type II error occurs when:
A.the null hypothesis is incorrectly accepted when it is false
B.the null hypothesis is incorrectly rejected when it is true
C.the sample mean differs from the population mean
D.the test is biased
Reset SelectionQuestion 2 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.More seniors are going to college
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.Cannot determine
D.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.
Reset SelectionQuestion 3 of 20 1.0 Points
The form of the alternative hypothesis can be:
A.two-tailed
B.one-tailed
C.neither one nor two-tailed
D.one or two-tailed
Reset SelectionQuestion 4 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.as many sets as necessary to cover all possibilities
D.two non-overlapping sets
Reset SelectionQuestion 5 of 20 1.0 Points
Which of the following statements are true of the null and alternative hypotheses?
A.It is possible for neither hypothesis to be true
B.Exactly one hypothesis must be true
C.It is possible for both hypotheses to be true
D.Both hypotheses must be true
Reset SelectionQuestion 6 of 20 1.0 Points
The hypothesis that an analyst is trying to prove is called the:
A.level of significance
B.quality of the researcher
C.alternative hypothesis
D.elective hypothesis
Reset SelectionQuestion 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 = 0.69
B.z = 1.96
C.z = 0.62
D.t = 1.645
Reset SelectionQuestion 8 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
Reset SelectionQuestion 9 of 20 1.0 Points
Suppose that the mean time for a certain car to go from 0 to 60 miles per hour was 7.7 seconds. Suppose that you want to test the claim that the average time to
accelerate from 0 to 60 miles per hour is longer than 7.7 seconds. What would you use for the alternative hypothesis?
A.H1: > 7.7 seconds
B.H1: 7.7 seconds
C.H1: = 7.7 seconds
D.H1: < 7.7 seconds
Reset SelectionQuestion 10 of 20 1.0 Points
If a teacher is trying to prove that a new method of teaching economics is more effective than a traditional one, he/she will conduct a:
A.two-tailed test
B.confidence interval
C.one-tailed test
D.point estimate of the population parameter
Reset SelectionQuestion 11 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: ≤ 1.2, H1: > 1.2
B.H0: ≠ 1.2, H1: = 1.2
C.H0: ≥ 1.2, H1: ≠ 1.2
D.H0: < 1.2, H1: ≠ 1.2
Reset Selection
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.
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 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 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 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 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 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.
Let x be a random variable representing dividend yield of Australian bank stocks. We may assume that x has a normal distribution with = 2.8%. A random sample of 16
Australian bank stocks has a sample mean dividend yield of 8.91%. For the entire Australian stock market, the mean dividend yield is = 6.4%. If you wanted to test to
determine if these data indicate that the dividend yield of all Australian bank stocks is higher than 6.4%, what is the value of the test statistic? Place your
answer, rounded to 3 decimal places, in the blank. For example, 2.345 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.
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 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.
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
Sample standard deviation 24.27
What is the test value that you would use to conduct this test? Place your answer, rounded to 3 decimal places in the blank. For example, 1.234 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
Reset SelectionQuestion 19 of 20 1.0 Points
Sample evidence is statistically significant at the level only if the p–value is larger than .
True False
Reset SelectionQuestion 20 of 20 1.0 Points
An alternative or research hypothesis is usually the hypothesis a researcher wants to prove.
True False
Reset Selection
24.
