The standard IQ test is designed so that the mean is 100 and the standard deviation is 15 for the population of all adults. We wish to find the sample size necessary to estimate the mean IQ score of statistics students. Suppose we want to be 90% confident that our sample mean is within 2 IQ points of the true mean. Assume then that o = 15 and determine the required sample size. (Be sure to round correctlyl)

The lengths of pregnancies in a small rural village are normally distributed with a mean of 265 days and a standard deviation of 16 days. In what range would you expect to find the middle 95% of most pregnancies? Between and If you were to draw samples of size 59 from this population, in what range would you expect to find the middle 95% of most averages for the lengths of pregnancies in the sample? Between and Enter your answers as numbers. Your answers should be accurate to 1 decimal places. Question Help: Message instructor Submit Question 824 tv esc 20 888 F1 F2 F3 F4 F5 F6 @ # $ % & 1 2 4 Q W Y T

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The lengths of pregnancies in a small rural village are normally distributed with a mean of 265 days and a standard deviation of 15 days. In what range would you expect to find the middle 50% of most pregnancies? Between and If you were to draw samples of size 58 from this population, in what range would you expect to find the middle 50% of most averages for the lengths of pregnancies in the sample? Between and Enter your answers as numbers. Your answers should be accurate to 1 decimal places.

We want to obtain a sample to estimate a population mean. Based on previous evidence, researchers believe the population standard deviation is approximately �=76.4. We would like to be 95% confident that the estimate is within 0.5 of the true population mean. How large of a sample size is required?�=

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