At an organization, scoring in the middle 80% of employees regarding job performance is designated as satisfactory. Job performance is a normally distributed variable. Individuals designated as having satisfactory job performance would have job performance scores that correspond with z-scores equal to or between _____.       a. z = -1.49 and z = +1.49   b. z = -0.39 and z = +0.39   c. z = -0.85 and z = +0.85   d. z = -1.28 and z = +1.28

A random sample of ten professional athletes produced the following data.  The first row is the number of endorsements the athlete has and the second row is the amount of money made (in millions of dollars) by the athlete.    What is the slope of the line of best fit?  Round to 3 decimal places. Number of Endorsements  0  3  2  1  5  5  4  3  0  4  Profit (in Millions)  2  8  7  3  13  12  9  9  3  10

A marketing firm is doing research for an internet-based company. It wants to appeal to the age group of people who spend the most money online. The company wants to know if there is a difference in the mean amount of money people spend per morith on Internet purchases depending on their age bracket. The marketing firm looked at two age groups, 18-24 years and 25-30 years, and collected the data shown in the following table. Let Population 1 be the amount of money spent per month on internet purchases by people in the 18-24 age bracket and Population 2 be the amount of money spent per month on internet purchases by people in the 25-30 age bracket. Assume that the population variances are not the same. Internet Spending per Month 18-24 Years Answer Mean Amount Spent Standard Deviation Sample Size Step 1 of 2: Construct a 99 % confidence interval for the true difference between the mean amounts of money per month that people in these two age groups spend on Internet purchases. Round the…

A County Board of Supervisors has appointed an urban planning committee to evaluate proposed community development projects. The committee is analyzing, among other things, data on household incomes in two cities within the county. They have collected data on the income of 80 households in each of the two cities. The histograms below show the distributions of the two sets of incomes (in thousands of dollars). Each histogram shows household income on the horizontal axis and number of households on the vertical axis. The means and standard deviations for the data sets are also given. City A City B 25- 25 - 20+ 20- 15- 15- 10+ 10- 5+ 5- 0- 10 20 30 40 50 60 70 80 90 100 10 20 30 40 50 60 70 80 90 100 City A mean: 38.13 thousand dollars City B mean: 55.13 thousand dollars City A standard deviation: 20.84 thousand dollars City B standard deviation: 14.71 thousand dollars The committee wants to use the Empirical Rule to make some approximations about both data sets. Unfortunately, it is…