all multiple choice statistics
1.
Two normal distributions are compared. One has a mean of 10 and a standard deviation of 10. The second normal distribution has a mean of 10 and a standard deviation of 2. Which of the following is true?
A) The locations of the distributions are different.
B) The distributions are from two different families of distributions.
C) The dispersions of the distributions are different.
D) The dispersions of the distributions are the same.
2.
When testing for differences between treatment means, a confidence interval is computed with __________________.
A) The mean square error
B) The standard deviation
C) The sum of squared errors
D) The standard error of the mean
3.
Which symbol represents a test statistic used to test a hypothesis about a population mean?
A) α
B) β
C) μ
D) z
4.
If all the plots on a scatter diagram lie on a straight line, what is the standard error of estimate?
A) -1
B) +1
C) 0
D) Infinity
5.
Twenty randomly selected statistics students were given 15 multiple-choice questions and 15 open-ended questions, all on the same material. The professor was interested in determining if students scored higher on the multiple-choice questions. This experiment is an example of ________________.
A) A one-sample test of means
B) A two-sample test of means
C) A paired t-test
D) A test of proportions
6.
An ANOVA has three sources of variation. They are _____, _____, and _____.
7.
The Intelligence Quotient (IQ) test scores for adults are normally distributed with a mean of 100 and a standard deviation of 15. What is the probability we could select a sample of 50 adults and find the mean of this sample is less than 95?
A) 0.0091
B) 0.9818
C) 0.4909
D) 0.9544
8.
What distribution does the F distribution approach as the sample size increases?
A) Binomial
B) Normal
C) Poisson
D) Exponential
9.
A national manufacturer of unattached garages discovered that the distribution of the time for two construction workers to erect the Red Barn model is normally distributed with a mean of 32 hours and a standard deviation of 2 hours. What percent of the garages take between 32 and 34 hours to erect?
A) 16.29%
B) 76.71%
C) 3.14%
D) 34.13%
10.
The F distribution is a ______________ distribution.
11.
The mean weight of trucks traveling on a particular section of I-475 is not known. A state highway inspector needs an estimate of the population mean. He selects and weighs a random sample of 49 trucks and finds the mean weight is 15.8 tons. The population standard deviation is 3.8 tons. What is the 95% confidence interval for the population mean?
A) 14.7 and 16.9
B) 13.2 and 17.6
C) 10.0 and 20.0
D) 16.1 and 18.1
12.
A student wanted to construct a 95% confidence interval for the mean age of students in her statistics class. She randomly selected nine students. Their average age was 19.1 years with a sample standard deviation of 1.5 years. What is the best point estimate for the population mean?
A) 2.1 years
B) 1.5 years
C) 19.1 years
D) 9 years
13.
The statistical technique used to test the equality of three or more population means is ___________________.
14.
In ANOVA analyses, when the null hypothesis is rejected, we can test for differences between treatment means by _____________.
A) Constructing confidence intervals
B) Adding another treatment
C) Doing an additional ANOVA
D) Doing a t test
15.
Based on the Nielsen ratings, the local CBS affiliate claims its 11 p.m. newscast reaches 41% of the viewing audience in the area. In a survey of 100 viewers, 36% indicated that they watch the late evening news on this local CBS station. What is the sample proportion?
A) 0.41
B) 0.36%
C) 0.41%
D) 0.36
16.
When H0: is rejected in ANOVA, we compute ____________ to identify pairs of means that differ.
17.
Three different fertilizers were applied to a field of celery. In computing F, how many degrees of freedom are there in the numerator?
A) 0
B) 1
C) 2
D) 3
18.
A sample of 250 adults tried the new multigrain cereal “Wow!” A total of 187 rated it as excellent. In a sample of 100 children, 66 rated it as excellent. Using the 0.1 significance level, the researcher wishes to show that adults like the cereal better than children. What test statistic should we use to compare the ratings of adults and children?
A) A z-statistic
B) A right one-tailed test statistic
C) A left one-tailed test statistic
D) A t-statistic
19.
When is it appropriate to use the paired difference t-test?
A) When four samples are compared at once
B) When any two samples are compared
C) When two independent samples are compared
D) When two dependent samples are compared
20.
What does a coefficient of correlation of 0.70 infer?
A) There is almost no correlation because 0.70 is close to 1.0.
B) 70% of the variation in one variable is explained by the other variable.
C) The coefficient of determination is 0.49.
D) The coefficient of nondetermination is 0.30.
21.
If the correlation between two variables is close to one, the association between the variables is ___________.
A) Strong
B) Moderate
C) Weak
D) Zero
22.
If we reject the null hypothesis, H0: , what can we conclude about the population correlation coefficient?
A) It is zero.
B) It could be zero.
C) It is not zero.
D) It equals the computed sample correlation.
23.
A university surveyed recent graduates of the English Department for their starting salaries. Four hundred graduates returned the survey. The average salary was $25,000, with a standard deviation of $2,500. What is the best point estimate of the population mean?
A) $25,000
B) $2,500
C) $400
D) $62.5
24.
Based on the Nielsen ratings, the local CBS affiliate claims its 11 p.m. newscast reaches 41% of the viewing audience in the area. In a survey of 100 viewers, 36% indicated that they watch the late evening news on this local CBS station. What is the z test statistic?
A) 1.02
B) 1.22
C) -1.02
D) -1.22
25.
For an alternative hypothesis: µ > 6,700, where is the rejection region for the hypothesis test located?
A) In both tails
B) In the left or lower tail
C) In the right or upper tail
D) In the center
26.
The mean annual incomes of certified welders are normally distributed with the mean of $50,000 and a standard deviation of $2,000. The ship building association wishes to find out whether their welders earn more or less than $50,000 annually. The alternate hypothesis is that the mean is not $50,000. If the level of significance is 0.10, what is the critical value?
A) +1.645
B) -1.282
C) ±1.282
D) ±1.645
27.
When testing the null hypothesis that two population means are equal, the hypothesized difference between the population means is ________________.
28.
There are 2,000 eligible voters in a precinct. A total of 500 voters are randomly selected and asked whether they plan to vote for the Democratic incumbent or the Republican challenger. Of the 500 surveyed, 350 said they would vote for the Democratic incumbent. Using the 0.99 confidence coefficient, what are the confidence limits for the proportion that plan to vote for the Democratic incumbent?
A) 0.647 and 0.753
B) 0.612 and 0.712
C) 0.397 and 0.797
D) 0.826 and 0.926
29.
Bones Brothers & Associates prepare individual tax returns. Over prior years, Bones Brothers has maintained careful records regarding the time to prepare a return. The mean time to prepare a return is 90 minutes and the standard deviation of this distribution is 14 minutes. Suppose 100 returns from this year are selected and analyzed regarding the preparation time. What is the probability that the mean time for the sample of 100 returns for this year is greater than 92?
A) Approximately zero
B) 0.0832
C) 0.4168
D) 0.0764
30.
If the correlation coefficient between two variables, X and Y, equals zero, what can be said of the variables X and Y?
A) The variables are not related.
B) The variables are dependent on each other.
C) The variables are highly related.
D) X causes Y.
31.
Which condition must be met to conduct a test for the difference in two sample means using a z-statistic?
A) The data must be at least of nominal scale.
B) The populations must be normal.
C) The two population standard deviations must be known.
D) The samples are dependent.
32.
The size of the sampling error is ________.
A) Directly related to the sample size—in other words, the larger the sample size, the larger the sampling error
B) Directly related to the population mean—in other words, the larger the mean, the larger the sampling error
C) Inversely related to the sample size—in other words, the larger the sample size, the smaller the sampling error
D) Inversely related to the population standard deviation—in other words, the smaller the standard deviation, the larger the sampling error
33.
In ANOVA analyses, when the null hypothesis is rejected, we can test for differences between treatment means by _____________.
A) Constructing confidence intervals
B) Adding another treatment
C) Doing an additional ANOVA
D) Doing a t test
34.
A marketing firm is studying consumer preferences for winter fashions in four different months. From a population of women 18-21 years of age, a random sample of 100 women was selected in January. Another random sample of 100 women was selected in March. Another random sample of 100 women was selected in June. Another random sample of 100 women was selected in September. What is the number of samples?
A) 4
B) 100
C) 400
D) 1
35.
According to the central limit theorem, ____________.
A) The population mean and the mean of all sample means are equal
B) Increasing sample size decreases the dispersion of the sampling distribution
C) The sampling distribution of the sample means is approximately normally distributed
D) The sampling distribution of the sample means will be skewed
36.
A group of statistics students decided to conduct a survey at their university to find the average (mean) amount of time students spent studying per week. They sampled 240 students and found a mean of 22.3 hours per week. Assuming a population standard deviation of six hours, what is the 99% level of confidence?
A) [21.80, 22.80]
B) [16.3, 28.3]
C) [21.30, 23.30]
D) [20.22, 22.0]
37.
A survey of an urban university (population of 25,450) showed that 750 of 1,100 students sampled attended a home football game during the season. Using the 90% level of confidence, what is the confidence interval for the proportion of students attending a football game?
A) [0.7510, 0.8290]
B) [0.6569, 0.7031]
C) [0.6659, 0.6941]
D) [0.6795, 0.6805]
38.
The number of trials and the population proportion are respectively represented by what symbols?
A) p and n
B) α and β
C) z and t
D) n and π
39.
For a normal distribution, what is the likelihood (expressed as a percentage) that a random variable is within plus and minus two standard deviations of the mean?
A) 68.26%
B) 99.74%
C) 34.13%
D) 95.44%
40.
Which of the following is a characteristic of the normal probability distribution?
A) It’s positively skewed.
B) It’s bell-shaped.
C) It’s asymmetrical.
D) It’s rectangular.
41.
Of the following characteristics, the t distribution and z distribution are the same in all BUT one. Which one is it?
A) Continuous
B) Symmetrical
C) Bell-shaped
D) Mean = 0, and standard deviation = 1
42.
A survey of 25 grocery stores revealed that the mean price of a gallon of milk was $2.98, with a standard error of $0.10. What is the 95% confidence interval to estimate the true cost of a gallon of milk?
A) $2.81 to $3.15
B) $2.94 to $3.02
C) $2.77 to $3.19
D) $2.95 to $3.01
43.
In plotting paired data in a scatter diagram, the dependent variable is scaled on the __________________.
44.
The paired t test is especially appropriate when the two samples are ________.
45.
The time to fly between New York City and Chicago is uniformly distributed with a minimum of 120 minutes and a maximum of 150 minutes. What is the probability that a flight is less than 135 minutes?
A) 1.00
B) 0.50
C) 0.25
D) 0.00
46.
Suppose a research firm conducted a survey to determine the mean amount steady smokers spend on cigarettes during a week. A sample of 100 steady smokers revealed that the sample mean is $20 and the sample standard deviation is $5. What is the probability that a sample of 100 steady smokers spend between $19 and $21?
A) 0.4772
B) 0.0228
C) 0.9544
D) 1.0000
47.
When independent samples with unknown but equal standard deviations are used to test for differences in the means, we pool the sample _________________.
48.
It is claimed that in a bushel of peaches, less than 10% are defective. A sample of 400 peaches is examined and 50 are found to be defective. What is the null hypothesis?
A) H0: π ≠ 0.10
B) H0: π ≥ 0.10
C) H0: π ≤ 0.10
D) H0: π < 0.10
49.
Customers of the Key Refining Company charge an average of $70 per month. The distribution of amounts charged is approximately normal, with a standard deviation of $10. What is the probability of selecting a credit card customer at random and finding the customer charged between $70 and $83?
A) 0.1962
B) 0.4032
C) 0.3413
D) 0.4750
50.
What is an important similarity between the uniform and normal probability distributions?
A) The mean, median, and mode are all equal.
B) The mean and median are equal.
C) They are negatively skewed.
D) About 68% of all observations are within one standard deviation of the mean.
