A researcher is interested in testing whether college students send more or fewer texts per day, relative to the general population. The researcher finds out that the population average of texts sent per day is µ = 112, but is unable to find out the population standard deviation. This researcher then recruits 25 college students, and asks about their texting. They report a sample mean of M = 120, with a SS= 1200 Compute the sample variance s2=  ?

The mean tar content of a simple random sample of 25 unfiltered king-size cigarettes is 21.4 mg, with a standard deviation of 3 mg. The mean tar content of a simple random sample of 25 filtered 100-mm cigarettes is 13.0 mg with a standard deviation of 3.8 mg. The accompanying table shows the data. Assume that the two samples are independent simple random samples selected from normally distributed populations, and do not assume that the population standard deviations are equal. Let population 1 be unfiltered king-size cigarettes. Complete parts (a) through (c) below. Click the icon to view the data. a. Use a 0.05 significance level to test the claim that unfiltered king-size cigarettes have a mean tar content greater than that of filtered 100-mm cigarettes. What does the result suggest about the effectiveness of cigarette filters? Identify the null and alternative hypotheses. O B. Ho: H1 =H2 O C. Ho: H1 #H2 H1: H1 =H2 O A. Ho: H1 = H2 H:H1 H2 O F. Ho: H1 = H2 H1:H1> H2 H:H1=H2 Hq: H1…

A researcher was interested in knowing if mean BMI was different between males and females. He obtained the following test results. Choose the correct interpretation of the results: F test p value = 0.30 Two sample t test, assume equal variance = 0.02 Two sample t test, assume unequal variance = 0.61 Mean BMI is not significantly different between males and females. None Mean BMI is higher in males than females. Mean BMI is significantly different between males and females.

A report stated that after obtaining a bachelor's degree, 43% of college students enroll in a graduate degree program. For a random sample of 61 undergraduate students, find the mean, variance and standard deviation for the number of students who will enroll in a graduate degree program after obtaining a bachelor's degree. a.) mean b.) variance c.) standard deviation (round to two decimal places)

. Each member of a large genetics class grows 12 pea plants from an independent pea family. Each family is expected to have 3/4 plants with smooth peas and 1/4 plants with wrinkled peas. a. On average, how many wrinkled pea plants will a student see in her 12 plants? b. What is the standard deviation of the proportion of wrinkled pea plants per student? c. What is the variance of the proportion of wrinkled pea plants per student? d. Predict what proportion of the students saw exactly two wrinkled pea plants in their sample.

An article in a Journal reports that 34% of American fathers take no responsibility for childcare. A researcher claims that the figure is higher for fathers in the town of Littleton. A random sample of 234 fathers from Littleton yielded 96 who did not help with childcare. How many populations? 01 What is the parameter? O Mean O Proportion O Difference between Means O Variance Standard Deviation

The salaries of professional baseball players are heavily skewed right with a mean of $3.2 million and a standard deviation of $2 million. The salaries of professional football players are also heavily skewed right with a mean of $1.9 million and a standard deviation of $1.5 million. A random sample of 40 baseball players’ salaries and 35 football players’ salaries is selected. The mean salary is determined for both samples. Let  represent the difference in the mean salaries for baseball and football players. Which of the following represents the shape of the sampling distribution for ? skewed right since the populations are both right skewed skewed right since the differences in salaries cannot be negative approximately Normal since both sample sizes are greater than 30 approximately Normal since the sum of the sample sizes is greater than 30