he cost of textbooks is normally distributed with a mean of $249. You do not know the population standard deviation, but you estimate the sample standard deviation to be $41. What is the probability that from a sample of 4 textbooks, their average cost will be between $224 and $266?
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.
The cost of textbooks is
What is the
Given Information:
The cost of textbooks is normally distributed with a mean of $249.
Mean = 249
Standard deviation (s) = 41
Sample size (n) = 4
To find the probability that from a sample of 4 textbooks, their average cost will be between $224 and $266:
Standard error =
Z-score is a measure which tells how many standard deviations away a data value is, from the mean. It is given by the formula:
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