Stat Test Review
Test4 review SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
Provide an appropriate response.
1) The dean of a major university claims that the mean time for students to earn a Masterʹs degree is at most 4.9 years. Write the null and alternative hypotheses.
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2) The mean score for all NBA games during a particular season was less than 101 points per game. State this claim mathematically. Write the null and alternative hypotheses. Identify which hypothesis is the claim.
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3) Given H0: p ≥ 80% and Ha: p < 80%, determine whether the hypothesis test is left-tailed, right-tailed, or two-tailed.
A) right-tailed B) left-tailed C) two-tailed
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4) A researcher claims that 62% of voters favor gun control. Determine whether the hypothesis test for this claim is left-tailed, right-tailed, or two-tailed.
A) left-tailed B) two-tailed C) right-tailed
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SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
5) The mean age of bus drivers in Chicago is 52.5 years. Identify the type I and type II errors for the hypothesis test of this claim.
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6) The mean age of bus drivers in Chicago is 59.3 years. If a hypothesis test is performed, how should you interpret a decision that fails to reject the null hypothesis?
A) There is sufficient evidence to support the claim μ = 59.3.
B) There is sufficient evidence to reject the claim μ = 59.3.
C) There is not sufficient evidence to support the claim μ = 59.3.
D) There is not sufficient evidence to reject the claim μ = 59.3.
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7) The mean IQ of statistics teachers is greater than 160. If a hypothesis test is performed, how should you interpret a decision that rejects the null hypothesis?
A) There is not sufficient evidence to reject the claim μ > 160.
B) There is sufficient evidence to reject the claim μ > 160.
C) There is sufficient evidence to support the claim μ > 160.
D) There is not sufficient evidence to support the claim μ > 160.
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8) Given H0: μ ≤ 12, for which confidence interval should you reject H0?
A) (11.5, 12.5) B) (10, 13) C) (13, 16)
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9) Suppose you are using α = 0.05 to test the claim that μ > 14 using a P-value. You are given the sample statistics n = 50, x = 14.3, and s = 1.2. Find the P-value.
A) 0.0128 B) 0.0384 C) 0.1321 D) 0.0012
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10) Given H0: μ ≥ 18 and P = 0.070. Do you reject or fail to reject H0 at the 0.05 level of significance?
A) not sufficient information to decide
B) reject H0
C) fail to reject H0
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SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
11) A fast food outlet claims that the mean waiting time in line is less than 3.4 minutes. A random sample of 60 customers has a mean of 3.3 minutes with a standard deviation of 0.6 minute. If α = 0.05, test the fast food outletʹs claim.
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12) You wish to test the claim that μ > 32 at a level of significance of α = 0.05 and are given sample statistics n = 50, x = 32.3, and s = 1.2. Compute the value of the standardized test statistic. Round your answer to two decimal places.
A) 1.77 B) 3.11 C) 0.98 D) 2.31
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13) Suppose you want to test the claim that μ ≥ 65.4. Given a sample size of n = 35 and a level of significance of α = 0.05, when should you reject H0?
A) Reject H0 if the standardized test statistic is less than -1.28.
B) Reject H0 if the standardized test statistic is less than -2.575.
C) Reject H0 if the standardized test is less than -1.96.
D) Reject H0 if the standardized test statistic is less than -1.645.
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14) Find the standardized test statistic t for a sample with n = 12, x = 22.2, s = 2.2, and α = 0.01 if H0: μ = 21. Round your answer to three decimal places.
A) 2.001 B) 1.890 C) 2.132 D) 1.991
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SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
15) A local group claims that the police issue more than 60 speeding tickets a day in their area. To prove their point, they randomly select two weeks. Their research yields the number of tickets issued for each day. The data are listed below. At α = 0.01, test the groupʹs claim using P-values.
70 48 41 68 69 55 70 57 60 83 32 60 72 58
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16) Determine whether the normal sampling distribution can be used. The claim is p < 0.25 and the sample size is n = 18.
A) Use the normal distribution. B) Do not use the normal distribution.
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SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
17) An airline claims that the no-show rate for passengers is less than 5%. In a sample of 420 randomly selected reservations, 19 were no-shows. At α = 0.01, test the airlineʹs claim.
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18) Compute the standardized test statistic, X2, to test the claim σ2 = 21.5 if n = 12, s2 = 18, and α = 0.05.
A) 9.209 B) 18.490 C) 12.961 D) 0.492
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SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
19) A trucking firm suspects that the variance for a certain tire is greater than 1,000,000. To check the claim, the firm puts 101 of these tires on its trucks and gets a standard deviation of 1200 miles. If α = 0.05, test the trucking firmʹs claim using P-values.
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Identify the explanatory variable and the response variable.
20) An agricultural business wants to determine if the rainfall in inches can be used to predict the yield per acre on a wheat farm.
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Provide an appropriate response.
21) The data below are the gestation periods, in months, of randomly selected animals and their corresponding life spans, in years. Construct a scatter plot for the data. Determine whether there is a positive linear correlation, a negative linear correlation, or no linear correlation.
Gestation, x 8 2.1 1.3 1 11.5 5.3 3.8 24.3 Life span, y 30 12 6 3 25 12 10 40
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22) The data below are the number of absences and the final grades of 9 randomly selected students from a statistics class. Calculate the correlation coefficient, r.
Number of absences, x Final Grade, y
1 97
4 85
7 79
5 81
10 70
3 91
16 54
9 75
6 81
A) -0.918 B) -0.899 C) -0.991 D) -0.888
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23) Given a sample with r = -0.765, n = 22, and α = 0.02, determine the critical values t0 necessary to test the claim ρ = 0.
A) ± 2.528 B) ± 2.831 C) ± 1.721 D) ± 2.080
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24) Find the equation of the regression line for the given data.
x y
-5 11
-3 -6
4 8 1 -3
-1 -2
-2 1 0 5 2 -5
3 6 -4 7
A) y ^ = -2.097x + 0.206 B) y
^ = 0.206x – 2.097
C) y ^ = 2.097x – 0.206 D) y
^ = -0.206x + 2.097
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25) Use the regression equation to predict the value of y for x = -1.5. Assume that the variables x and y have a significant correlation.
x y
-5 11
-3 6 4 -6
1 -1
-1 3 -2 4 0 1 2 -4
3 -5
-4 8
A) -2.069 B) -3.022 C) 3.586 D) 0.748
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SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
26) Find the equation of the regression line by letting Row 1 represent the x-values and Row 2 represent the y-values. Now find the equation of the regression line letting Row 2 represent the x-values and Row 1 represent the y-values. What effect does switching the explanatory and response variables have on the regression line?
Row 1 Row 2
-5 -10
-3 -8
4 9
1 1
-1 -2
-2 -6
0 -1
2 3
3 6
-4 -8
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27) Find the standard error of estimate, se, for the data below, given that y ^ = -2.5x.
x y -1 2
-2 6
-3 7
-4 10
A) 0.675 B) 0.349 C) 0.532 D) 0.866
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SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
28) Calculate the coefficient of determination, given that the linear correlation coefficient, r, is -0.625. What does this tell you about the explained variation and the unexplained variation of the data about the regression line?
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29) Construct a 95% prediction interval for y given x = 2.5, y ^ = -2.5x and se = 0.866. Round interval to
three decimal places.
x y
-1 2
-2 6
-3 7
-4 10
A) -16.156 < y < 3.656 B) -15.566 < y < 3.066
C) -8.244 < y < -4.256 D) -12.594 < y < 0.094
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30) A multiple regression equation is y ^ = -35,000 + 130×1 + 20,000×2, where x1 is a personʹs age, x2 is
the personʹs grade point average in college, and y is the personʹs income. Predict the income for a person who is 34 years old and had a college grade point average of 2.5.
A) $19,420 B) $645,325 C) $54,420 D) $89,420
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SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
31) The frequency distribution shows the ages for a sample of 100 employees. Find the…
