A group of statistics students decided to conduct a survey at their university to find the average (mean) amount of time students spent studying per week. Assuming a population standard deviation of three hours, what is the required sample size if the error should be less than a half hour with a 99% level of confidence?

To be considered statistically valid, any sampling procedure must include some form of _____________________________________.

A regression model between sales (y in $1000), unit price (x1 in dollars), and television advertisement (x2 in dollars) resulted in the following function: ​ Y = 7 – 3×1 + 5×2​ ​  The coefficient of x2 indicates that if television advertisement is increased by $1 (holding the unit price constant), sales are expected to

If r = 0.65, what does the coefficient of determination equal?  

. A random sample consisting of the values listed below was taken from a normally distributed population.  Assuming the standard deviation of the population is unknown, construct a 99% confidence interval for the population mean that these samples were taken from. (27.4, 26.5, 25.7, 31.4, 28.2, 21.9, 16.3, 22.7, 18.8, 34.4, 29.2, and 20.5)  

Which of the following are true assumptions underlying linear regression?   (1) For each value of X, there is a group of Y values that is normally distributed. (2) The means of these normal distributions of Y values all lie on the regression line. (3) The standard deviations of these normal distributions are equal.  

In what type of distribution is a z-score utilized?

If someone has already answered the question online (like on Chegg or in a discussion forum on Canvas), then it’s public information that’s free to use and not academic dishonesty.  

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The text book Guidance of young children (10th ed.) by Marion is required for this course.  A used copy or eBook is fine.  The MyEducationLab access code is NOT required for this course.