Exam 3: Numerical Descriptive Measures

The empirical rule can be used to estimate some proportions when data has what shape?

A bowler's scores for a sample of six games were The bowler's median score is:

The following is a list of GPA ranges and frequencies from a high school.Use 1.5 as the midpoint of the 2.0 or less category. a.What is the mean GPA? B)What is the sample standard deviation of the GPA C)Assuming the distribution is bell shaped what percentage of the students would have GPA's between 1.5 and 3.9? Does this make sense given what you know about GPA's?

Approximately 60% of the observations in a data set fall below the 60^th percentile.

Your used car is expected to last an average of 200,000 miles with a standard deviation of 25,000 miles before it requires a new transmission. A)Use Chebyshev's Theorem to approximate the probability that the engine will last between 150,000 miles and 250,000 miles. B)Assume a symmetric bell-shaped distribution to approximate the probability that the engine will last between 150,000 miles and 250,000 miles.

The empirical rule is only applicable for approximately bell-shaped data.

What is the interquartile range?

Professors at a local university earn an average salary of $80,000 with a standard deviation of $6,000.The salary distribution is approximately bell-shaped.Because of budget limitations,it has been decided that only those whose salaries are approximately in the bottom 2.5% would get a raise.What is the maximum current salary that qualifies for the raise?

Chebyshev's theorem is applicable when the data are

Is it possible for a data set to have no mode?

Consider the following data: 1,2,4,5,10,12,18.The 30^th percentile is closest to:

What is (are)the most widely used measure(s)of dispersion?

A bowler's scores for a sample of six games were The sample standard deviation is closest to:

An analyst gathered the following information about the net profit margins of companies in two industries: Compared with the other industry,the relative dispersion of net profit margins is smaller for Industry:

Automobiles traveling on a road with a posted speed limit of 65 miles per hour are checked for speed by a state police radar system.The following is a frequency distribution of speeds. The standard deviation of this distribution is closest to:

Professors at a local university earn an average salary of $80,000 with a standard deviation of $6,000.The salary distribution is approximately bell-shaped.What can be said about the percentage of salaries that are less than $68,000 or more than $92,000?

A bowler's scores for a sample of six games were The bowler's average score is:

What is the relationship between the variance and the standard deviation?

The following sample data shows the starting salaries of six graduates from the Accounting Program at California Polytechnic State University.The data is in thousands of dollars. 24,46,48,52,56,58,60 A)Calculate and interpret the 25^th,50^th and 75^th percentiles. B)Are there any outliers? Is the distribution symmetric? If not,comment on its skewness.

How do we find the median if the number of observations in a data set is odd?