A random sample of 36 textbook prices is taken from a local college bookstore. The mean of the sample is x= 72 , the sample standard deviation is s = 24, and the population is normally distributed. You want to estimate the mean price of all the textbooks in the college bookstore. How many books must be included in your sample if you want to be 95% confident that the sample mean is within $4 of the population mean?
Inverse Normal Distribution
The method used for finding the corresponding z-critical value in a normal distribution using the known probability is said to be an inverse normal distribution. The inverse normal distribution is a continuous probability distribution with a family of two parameters.
Mean, Median, Mode
It is a descriptive summary of a data set. It can be defined by using some of the measures. The central tendencies do not provide information regarding individual data from the dataset. However, they give a summary of the data set. The central tendency or measure of central tendency is a central or typical value for a probability distribution.
Z-Scores
A z-score is a unit of measurement used in statistics to describe the position of a raw score in terms of its distance from the mean, measured with reference to standard deviation from the mean. Z-scores are useful in statistics because they allow comparison between two scores that belong to different normal distributions.
A random sample of 36 textbook prices is taken from a local college bookstore. The
You want to estimate the mean price of all the textbooks in the college bookstore. How many books must be included in your sample if you want to be 95% confident that the sample mean is within $4 of the population mean?
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