he president of a university believes the entering class this year has an average ACT score different than previous years. The average ACT score previously had been 23. He took a sample of 100 students from this year’s entering class and found their sample mean ACT score is 24 with a sample standard deviation of 6. Is there evidence the population mean ACT score is different from 23 at the 0.01 significance level? State the correct decision rule for α = 0.01. Note: |Tstat| means the absolute value of the test statistic
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 president of a university believes the entering class this year has an average ACT score different than previous years. The average ACT score previously had been 23. He took a sample of 100 students from this year’s entering class and found their sample
State the correct decision rule for α = 0.01.
Note: |Tstat| means the absolute value of the test statistic
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