A graphical device that highlights the highest and lowest values in a data set, along with a number of other key observations in an ordered array of the data, such as the upper quartile, the middle value (or median), and the lower quartile, is called:
a. a boxplot
b. a five-number summary
c. a dotplot
d. a stem-and-leaf plot
e. a histogram
Q. 2A pooled estimate for any statistic in a problem dealing with two populations is a value arrived at by combining the two separate sample statistics so as to achieve the best possible point estimate.
Indicate whether the statement is true or false
Q. 3The percentage of all observations in a data set that lies between the 30th percentile and the third quartile:
a. equals 30
b. equals 45
c. equals 75
d. equals 85
e. cannot be determined without additional information
Q. 4The standard normal score is used for all inferences concerning population proportions.
Indicate whether the statement is true or false
Q. 5An exam is given to both the fourth period class and the sixth period class. If a student's score is at the 30th percentile in the fourth period class but at the 60th percentile in the sixth period class, which one of the following statements is true?
a. Students in the sixth period class generally performed better on the exam than the students in the fourth period class.
b. A person whose score is at the 15th percentile in the fourth period class will have a score at the 30th percentile in the sixth period class.
c. A person whose score is at the 70th percentile in the sixth period class will have a score at the 40th percentile in the fourth period class.
d. Students in the fourth period class generally performed better on the exam than students in the sixth period class.
e. None of these.
Q. 6When we test a null hypothesis about the difference between two population means, using two independent samples, the test statistic used will be the difference between the observed difference of the sample means and the hypothesized difference of the population means, divided by the estimated standard error.
Indicate whether the statement is true or false
Q. 7Which of the following summary measures is affected most by outliers?
a. the first quartile
b. the second quartile
c. the third quartile
d. the fourth quartile
e. none of these
Q. 8If we are testing for the difference between two independent population means, it is assumed that the two populations are approximately normal and have equal variances.
Indicate whether the statement is true or false
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