In a sample of 50 business trips taken by employees in the HR department, a company finds that the average amount spent for the trips was $1450 with a standard deviation of $450. In a sample of 90 trips taken by the employees in the sales department is $1650 with a standard deviation of $550. When testing the hypothesis (at the 10% level of significance) that the variance of the amount spent on trips is significantly larger in one department than the other, if the p-value 0.063, what is your conclusion concerning the null hypothesis   select  a) reject null hypothesis  or  b) fail to reject null hypothesi

A newspaper reporter is writing an article on employment status for young people who don’t have a high school diploma.  She obtains employment data from 24 randomly selected full-time young male workers without a high school diploma.  This data has a sample mean of $24,970 with standard deviation of $2300.  Using this sample data to test the claim that the mean annual salary of all full-time young male workers (without a high school diploma) is different from $26,000, we get the following results from the TI-84. Using a 0.05 level of significance, state the conclusion in terms of the given claim and explain how this conclusion was reached

In a study investigating the effect of car speed on accident severity, 5,000 reports of fatal automobile accidents were examined, and the vehicle speed at impact was recorded for each one. For these 5,000 accidents, the average speed was 54 mph and the standard deviation was 11 mph. A histogram revealed that the vehicle speed at impact distribution was approximately normal. (Use the Empirical Rule.) (a) Approximately what percentage of these vehicle speeds were between 43 and 65 mph? (b) Approximately what percentage of these vehicle speeds exceeded 65 mph? Step 1 (a) Approximately what percentage of these vehicle speeds were between 43 and 65 mph? Recall that per the Empirical Rule, if a data distribution is mound shaped and approximately symmetric, then: • Approximately 68% of the observations fall within 1 standard deviation of the mean. Approximately 95% of the observations fall within 2 standard deviations of the mean. Approximately 99.7% of the observations fall within 3 standard…

The Wall Street Journal reported that automobile crashes cost the United States $162 billion annually (The Wall Street Journal, March 5, 2008). The average cost per person for crashes in the Tampa, Florida, area was reported to be $1613. Suppose this average cost was based on a sample of 55 persons who had been involved in car crashes and that the population standard deviation is σ = 600. What would you recommend if the study required a margin of error of $150 or less?