Exam 4: Descriptive Statistics

Bob's sample of freshman GPAs showed a mean of 2.72 with a standard deviation of 0.31.(a)What range would you predict for all the grades? For the middle 95 percent? Explain.(b)Why might your estimates be inaccurate?

If samples are from a normal distribution with μ = 100 and σ = 10,we expect:

Given the data set 2,5,10,6,3,the median value is 3.

Which statement is false? Explain.

If there are 19 data values,the median will have 10 values above it and 9 below it since n is odd.

A smooth distribution with one mode is negatively skewed (skewed to the left).The median of the distribution is $65.Which of the following is a reasonable value for the distribution mean?

The athletic departments at 10 randomly selected U.S.universities were asked by the Equal Employment Opportunity Commission to state what percent of their nursing scholarships were presently held by women.The responses were 5,4,2,1,1,2,10,5,5,5.Find the mean,median,mode,and geometric mean.Which is the most appropriate measure of central tendency? The least appropriate? Explain your answer.Is there an outlier?

Given a sample of three items (X = 4,6,5)which statement is incorrect?

Patient waiting times in the Tardis Orthopedic Clinic have a mean of 50 minutes with a standard deviation of 25 minutes.Within what range would approximately 95 percent of the waiting times lie if we were sampling a normal distribution? Do you think the distribution is likely to be normal? Explain.

Which of the following statements is likely to be true?

Exam scores in a random sample of students were 0,50,50,70,70,80,90,90,90,100.Which statement is incorrect?

Which is true of the kurtosis of a distribution?

Which is a characteristic of the standard deviation?

What does the graph below (profit/sales ratios for 25 Fortune 500 companies)reveal?

A sample of 50 breakfast customers of MacDonald's showed the spending below.Which statement is least likely to be correct?

In Tokyo,construction workers earn an average of ×420,000 (yen)per month with a standard deviation of ¥20,000,while in Hamburg,Germany,construction workers earn an average of €3,200 (euros)per month with a standard deviation of €57.Who is earning relatively more,a worker making ¥460,000 per month in Tokyo or one earning €3,300 per month in Hamburg?

The range as a measure of variability is very sensitive to extreme data values.

The midhinge is a robust measure of center when there are outliers.

Here are advertised prices of 21 used Chevy Blazers.Describe the distribution (center,variability,shape).

A platykurtic distribution is more sharply peaked (i.e. ,thinner tails)than a normal distribution.