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If we reject the null hypothesis that tests a population correlation coefficient, what can we conclude about the correlation in the population?
Pennsylvania Refining Company is studying the relationship between the pump price of gasoline and the number of gallons sold. For a sample of 18 stations last Tuesday, the correlation was 0.67.
What is the decision rule? Use the .01 significance level. (Round your answer to 2 decimal places.)
Assume for now that the company chooses the two employees to be fired at random, so all possible pairs of people have the same probability of being fired.
In a specific chi-square goodness-of-fit test there are 6 categories and 500 observations. Use the 0.05 significance level.
Assume 80% of the incoming email messages for a college's computer system are spam.
Consider the experiment of tossing a pair of dice. Let X be the outcome (i.e., the number of dots appearing face up) on the first die and let Y be the outcome on the second die. Find the joint proba
For each of the following confidence intervals, indicate how much of the distribution would be placed in the cutoff region for a two tailed test.
Suppose that the mean hourly cost to operate a commercial airplane follows the normal distribution with a mean of $2,200 per hour and a standard deviation of $270.
If you're performing a hypothesis test using a z statistic in which you sampled 50 people and found an average SAT verbal score of 542 (assume we know the population mean to be 500 and the standard
A mandatory competency test for high school has a mean of 175 and a standard deviation of 20. The bottom 5% of the class will be required to attend summer school. What is the minimum score a studen
A poll stated that 32% of those polled think economy is getting worse. An economist wanted to check this claim so she surveyed 750 people and found that 30% of them thought economy is getting worse.
A normal population has a mean of 64 and a standard deviation of 13. You select a random sample of 9. Calculate the probability the sample mean is
For this question employ normal distribution approximation for the binomial distribution. Dottie's Tax Service specializes in federal tax returns for professional clients, such as physicians, dentis
Mattel Corporation produces remote-controlled car that needs three AA batteries. The mean life of these batteries in this product is 38 hours. The distribution of the battery lives closely follows t
An internal study by Technology Services department at Lahey Electronics revealed company employees receive average of 5.0 emails per hour. Suppose the arrival of these emails is approximated by the
A current study showed women spent average of 36 hours per week watching TV and men 30 hours per week. Suppose that the distribution of hours watched follows the normal distribution for both groups,
Examine the differences between the ANOVA statistic that is used to assess independent-measures designs with the ANOVA statistic that is used to assess repeated-measures designs.
If random assignment of patients to treatments did good job of eliminating bias, possible lurking variables such as smoking history, asthma, and hay fever should be similar in all 4 groups.
The annual per capita consumption of ice cream (in pounds) in the United States can be approximated by a normal distribution, as shown in the graph.
In determining the areas under the normal curve, if we wish to determine the area below A, and A is greater than the mean
In determining the areas under the normal curve, if we wish to determine the area above A, and A is greater than the mean
A researcher develop a repeated-measures experiment using a sample of n = 5 subjects to evaluate the differences among two treatment conditions. If the results are examined with ANOVA, what are the
234 employees chosen randomly from one company, 12.82 % of them commute by carpooling. Develop a 90% confidence interval for the true percentage of all employees of the company who carpool
A Machine is set to pump cleanser in a procedure at the rate of 7 gallons per minute. On inspection, it is learned that the machine actually pumps cleanser at the rate stated by the uniform distribu