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For a one-tailed hypothesis test, the critical z-value of the test statistic is -1.48. Which of the following is true about the hypothesis test?
What is the decision rule at the 0.01 level of significance to test if the new design increased the absorption amount of the sponge?
Using a 5% level of significance and a sample size of 26, what is the critical value for a one-tailed hypothesis test?
The table below lists the numbers of audience impressions listening to songs and the corresponding numbers of albums sold. Does it appear that album sales are affected very strongly by the number of
A student wanted to construct a 95% confidence interval for the average age of students in her statistics class. She randomly selected 11 students. Their average age was 21.4 years with a standard d
Recently, a university surveyed recent graduates of the English Department for their starting salaries. Four hundred graduates returned the survey. The average salary was $25,752. The population sta
A bank wishes to estimate the mean credit card balance owed by its customers. The population standard deviation is estimated to be $313. If a 98 percent confidence interval is used and an interval o
A group of statistics students decided to conduct a survey at their university to find the average (mean) amount of time students spend studying per week.
An accounting firm is planning for the next tax preparation season. From last year's returns, the firm collects a systematic random sample of 100 filings. The 100 filings showed an average preparati
What is the percentage of the total area under the normal curve within plus and minus 1.6 standard deviations of the mean?
The distribution of the annual incomes of a group of middle management employees approximated a normal distribution with a mean of $39,570 and a standard deviation of $798. About 65 percent of the i
How many main effects and interactions could you have in a 4 x 6 factorial design?
What internal and external validity threats did the researchers address in their design? How did they address them? Are there threats they did not address? If so how does the failure to address the
A sample of 20 items provides a sample standard deviation of 5. Compute the 95% confidence interval estimate of the population variance.
Construct a 95% interval estimate of the ratio of the population variances.
Imagine that the following sentence is from a Results section. Identify what is wrong with it. "There was a significant effect of gender at the .01 level, with a t-score of 10.2 for 9 degrees of fre
Conduct the appropriate analysis of these data and determine whether there are any significant differences.
Is there a difference in the amount of time it takes to develop anemia in patients with Head and Neck, Breast, Lung, and GI-Colorectal cancer? (Null and Alternative Hypothesis required).
In a test of weight loss programs, 198 subjects were divided such that 33 subjects followed each of 6 diets. Each was weighed a year after starting the diet and the results are in the ANOVA table be
Recent recommendations suggest 60 minutes of physical activity per day. A sample of 50 adults in a study of cardiovascular risk factors report exercising a mean of 38 minutes per day with a standard
Find the critical value ta(alpha)/2 that corresponds to a confidence level of 95% and a sample size of 11.
A researcher believes exercise reduces anxiety in women. She identifies a group of women who had not exercised before but are now planning to begin exercising.
Normal Distribution: If the mean per capita income in the U.S. is $39,000 and the standard deviation is 5000 - What percent of the population.
What is the mean number of people who will drop out of the Platinum Program in the first four weeks in a sample of this size? What is the standard deviation?