The interquartile range is found by taking the difference between the 1st and 3rd quartiles and dividing that value by 2.
Indicate whether the statement is true or false
Q. 2The interquartile range will always exceed that of the range.
Indicate whether the statement is true or false
Q. 3The distance between the 25th percentile and the median is always the same as the distance between the median and the 75th percentile.
Indicate whether the statement is true or false
Q. 4The price-earnings ratios of a sample of stocks have a mean value of 13.5 and a standard deviation of 2 . If the ratios have a bell shaped distribution, what can we say about the proportion of ratios that fall between
a. 11.5 and 15.5?
b. 9.5 and 17.5?
c. 7.5 and 19.5?
Q. 5A sample of 13 college professors has a mean age of 30 years and a standard deviation of 5 years. Suppose that the sample is enlarged to 15 college professors, by including two additional professors that are each 30 years old. Will the standard deviation increase, decrease, or stay the same, and why?
Q. 6The following data represent the number of children in a sample of 10 families from a certain community: 4, 2, 1, 1, 5, 3, 0, 1, 0, and 2.
a. Compute the range.
b. Compute the variance.
c. Compute the standard deviation.
d. Compute the coefficient of variation.
e. Explain why in this case range > variance > standard deviation > coefficient of variation.
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