A survey of 81 individuals finds that the average amount they spend on entertainment each month is £145 with a standard deviation of £54. i. Construct a 95% confidence interval for the true mean spend on entertainment. Interpret the results. ii. What sample size would be required to halve the confidence interval if the confidence level remains the same?
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 survey of 81 individuals finds that the average amount they spend on entertainment each month is £145 with a standard deviation of £54.
i. Construct a 95% confidence interval for the true
ii. What
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