Shifting data, by adding a constant to each data value, does not change the :

Based on a sample of 39 randomly selected years, a 90% confidence interval for the mean annual precipitation in one city is (45.36″ , 51.54″).  What is the margin of error for this interval?    

Mary, a statistics major, grows tomatoes in her spare time.  She keeps a record of the weight of each tomato she grows.  One tomato is 2 standard deviation heavier than the mean weight of her tomatoes.  Assume a Normal model is appropriate.  Approximately, what percentile is the weight of this tomato in?

Given independent random variables X and Y with means and standard deviations as shown, find the mean and standard deviation of  X-Y.  Justify your answer.      Mean        SD       X         86         4       Y         75          3

A recent newspaper article reported on Americans’ eating habits.  The article reported that only about one-third of American adults ate 2 or more servings of fruit per day, and only 26% ate 3 or more servings of vegetables per day.  Californians ate the most fruit, while Tennesseans ate the most vegetables.  The population in this study was:

The value of t* for a 98% confidence interval with sample size of n = 27 is    

Based on past experience, a bank believes that 12% of the people who receive loans will not make payments on time.  The bank has recently approved 100 loans.  The standard deviation of the sampling distribution model for proportion

What is the best description of this histogram?   

A student surveys customers at her local grocery store and asks for the respondent’s annual income.  She makes a histogram of the results, and reports the average (mean) to be $45,000.  You might expect this histogram to be

Suppose the lengths of green beans grown at a particular farm are Normally distributed with a mean of 7 inches and a standard deviation of 1.2 inches.  The z-score for a selected green bean is 2.3.  What does this tell us about the length of the selected green bean?