Suppose an education administrator wants to know whether the test scores of a new standardized graduation exam are different for males and females. To test this hypothesis, the administrator decides to perform a ?‑test for two independent means. She takes a random sample of test scores from both male and female populations. Some of the summary data are shown in the table. Population Population Description Sample size Sample mean (pts) Sample standard deviation (pts) 1 Female ?1=21 ?⎯⎯⎯1=34.3 ?1=3.09 2 Male ?2=22 ?⎯⎯⎯2=34.7 ?2=3.82 The administrator assumes that the population variances are equal, so she computes a pooled ?‑test statistic. Determine the number of degrees of freedom, df, for the pooled ?‑statistic.

IQ tests are approximately normally distributed with a mean of 100 for adults. A tech company CEO wants to conduct a hypothesis test to see if the average IQ of employees at high-tech firms in California is higher than average. What is Type I error in the context of this problem?

we look at a random sample of 1000 united flights in the month of December comparing the actual arrival time to the scheduled arrive time. computer  output of the descriptive statistics for the difference in actual and expected arrival time of these 1000 flights are shown below : N=1000 Mean =4.06  St Dev. = 45.4  SE Mean =1.44  Min= -35  Q1 = -14  Median = -5  Q3 =9  Max =871  what is the sample mean difference in actual and expected arrival times?  what is the standard deviation of the difference ? x bar =      and s=    ?

Suppose you have two samples with the following values: Sample 1: 2, 8, 6, 5, 4, 7, 5, 9, 6 Sample 2: 3, 5, 4, 8, 7, 5, 5, 7,6 For Sample 1, what are the values for: Mean Median Mode Standard Deviation Variance

How does an observed sample mean qualify as a rare outcome?

what is the answer?

Describe a study in which you can use both nonparametric and parametric statistics. A researcher has participants expecting to receive either painful or mild electrical shocks during a study wait in a quarter-full waiting room with other participants. He then measures whether they choose to sit next to other participants or if they sit far away on their own. What is the best test to run for this study and why?

A union of restaurant and foodservice workers would like to estimate the mean hourly wage, u, of foodservice workers in the U.S. this year The mean hourly wage last year was $8.16, and there is good reason to believe that this year's value is greater than last year's. The union decides to do a statistical test to see if the value has indeed increased. The union chooses a random sample of this year's wages, computes the mean of the sample to be $8.43, and computes the standard deviation of the sample to be $1.25. Based on this information, complete the parts below. (a) What are the null hypothesis H, and the alternative hypothesis H, that should be used for the test? H, :0 OSO H :0 D=0 (b) Suppose that the union decides not to reject the null hypothesis. What sort of error might it be making? (Choose one) (c) Suppose the true mean hourly wage for foodservice workers in the U.S. this year is $8.16. Fill in the blanks to describe a Type I error. A Type I error would be the hypothesis that…

The sample variances target the value of the population variance. true or false?

What is the symbol for the sample variance?