Exam 2: Describing Data With Numerical Measures

Height of Basketball Players A sample of basketball players has a mean height of 190 cm, with a standard deviation of 12 cm. You know nothing else about the size of the data set or the shape of the data distribution. -Refer to the Height of Basketball Players statement. What can you say about the fraction of measurements that fall between 154 and 226 cm?

Which of the following measures is NOT affected by extreme values in the data?

Consider this data set: 5, 6, 7, 11, and 15. Which of the following values equals its mean?

For any distribution, if the mean is equal to the standard deviation, you can conclude that the distribution is symmetric.

Flu Shot Eight doctors were asked how many flu shots they had given to patients this fall. The numbers of flu shots were 6, 3, 5, 24, 2, 6, 0, and 8. -Refer to Flu Shot statement. Find the sample mean.

Tchebysheff's Theorem applies only to data sets which have a mound-shaped distribution.

If the 18th and 19th observations in a set of 25 data values are 42.6 and 43.8, what is the 70th percentile value?

The distribution of chequing account balances for customers at Independent Bank is known to be bell-shaped with a mean of $1800 and a standard deviation of $300. Given this information, the percentage of accounts with balances between $1500 and $2100 is approximately 95%.

Consider the following set of measurements: 5.4, 5.9, 3.5, 4.1, 4.6, 2.5, 4.7, 6.0, 5.4, 4.6, 4.9, 4.6, 4.1, 3.4, and 2.2. a. Find the 25th, 50th, and 75th percentiles. b. What is the value of the interquartile range?

The mean is one of the most frequently used measures of variability.

The difference between the largest and smallest values in an ordered array is called the interquartile range.

A sample of 600 values produced the following summary statistics: and Given this information, which of the following values constitutes the lower fence on a box plot?

Optometrist Customers The following values denote the number of customers handled by an optometrist during a random sample of four periods of one hour each: 4, 6, 2, and 5. -Refer to the Optometrist Customers statement. Find the standard deviation of these values.

The sum of the deviations squared from the mean is always zero.

Half of the observations in a data set are on either side of the mean.

Which of the following is NOT a measure of variability?

Cracks in Bar The following data represent the number of small cracks per bar for a sample of eight steel bars: 4, 6, 10, 1, 3, 1, 25, and 8. -Refer to Cracks in Bar statement. What is the average number of small cracks per bar?

Community College Raises Assume that all employees of a community college received a monthly raise. -Refer to the Community College Raises statement. How would a $150 raise affect the mean of salaries? How would a $150 raise affect the standard deviation of salaries?

If a data set has 15 values that have been sorted in ascending order, which value in the data set will be at the 25th percentile?

Ice Cream Cone Sales A neighbourhood ice cream vendor reports the following sales of single-scoop ice cream cones (measured in hundreds of cones) for five randomly selected weeks: 5, 4, 6, 5, and 3. -The following data represent the sales (measured in $10,000s) of seven real estate salespersons employed by a local agency: 23, 34, 56, 47, 45, 60, and 249. Which measure of centre, the mean or the median, would provide a better measure of the average sales of the company? Give a reason for your answer.