An iq test is designed so that the mean is 100 and the standard deviation is 1313 for the population of normal adults. find the sample size necessary to estimate the mean iq score of statistics students such that it can be said with 9090% confidence that the sample mean is within 22 iq points of the true mean. assume that sigmaσ==1313 and determine the required sample size using technology. then determine if this is a reasonable sample size for a real world calculation.

Stu and ambrose are working together on a study of whether diet is related to students' mental health. first, they randomly select 10 students from the student center and 10 students from the office of counseling and psychological services. then, they ask students to rate their diet in terms of healthiness on a scale of 1-100 before completing a 20-item mental health survey. a) name one of the constructs being studied b) how was the construct you named above operationally defined in this experiment? e) was the variable you described above their independent variable, their dependent variable, or a controlled variable? d) what is a confounding variable? what is a potential confound in this study?

What is the value of x in the equation 3x4y65, when y=4?

Arandom sample of 45 observations results in a sample mean of 68. the population standard deviation is known to be 23 a. compute the margin of error at a 959% confidence interval. b. compute the 95% confidence interval for the population mean c. compute the 90% confidence interval for the population mean. d. compute the 75% confidence interval for the population mean