a) Kyle is working on a statistics problem and knows that the population standard deviation is 12.  He calculated a 99% confidence interval and determined that the error was 3.77. What was Kyle’s sample size? b). For a typical z-interval, the mean is 64, the standard deviation is 12, and the sample size is 81. If the interval is from 60.565 to 67.435, what is the  z*  value?, and what confidence level was used?

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Heights of men have a mean of 69.0 inches and a standard deviation of 2.8 inches.Find each of the following z-scores and tell if it is unusual. a) Nosferatu is 7 ft. 1 in. tall:  z =  and that is (unusual/not unusual) b) Bob the Builder is 5 ft. 4 in. tall:  z =  and that is (unusual/not unusual) c) Kendrick is 69.72 inches tall:  z =  and that is (unusual/not unusual)

For the given scenario, determine the type of error that was made if any.(begin by determining the null and alternative hypothesis). A new whitening toothpaste advertises for shades as the mean number of shades the toothpaste whitens your teeth. One user claims that the mean number of shades the toothpaste whitens your teeth is different from four shades. The user conducts a hypothesis test and fails to reject the null hypothesis. Assume that in reality, the mean number of shades the two piece white is your teeth is for shade. Was an error made? If so, what type? A, B, C? A.Yes; type 2 error B.Yes; type 1 error C.No; correct decision

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Can someone explain the formulas used in these type of questions and where each number belongs in the formula     The average size of a farm in Texas is 185 acres. The average size of a farm in Kansas is 220 acres. Assume that the data were obtained from two samples with standard deviations of 40 and 15 acres, respectively, and a sample size of 10 and 12, respectively. Can it be concluded with a=0.05 that the average size of the farms in the two states is different? Assume that the population is normally distributed.