The Jimmy John’s store manager on Hwy. 46 wanted to know more about their customers. She decides to focus on two variables: the average ticket spent by customers, and whether customers would consider purchasing ice cream if it was available. She interviewed 54 customers over a two-week period. Results of her research showed average ticket was $10.89 with a standard deviation of $2.35. Twenty-two customers said they would purchase ice cream if it was available. a. Construct a 95% confidence interval estimate for the population mean ticket. b. Construct a 90% confidence interval estimate for the population proportion of customers who would consider purchasing ice cream. Assume the store manager wants to conduct a similar survey at the National Road store. Answer the following questions: c. What sample size is needed to have 95% confidence of estimating the population average ticket in this store to within plus/minus $1.00 if the standard deviation is assumed to be $2.35? d. How many customers need to be selected to have 90% confidence of estimating the p
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 Jimmy John’s store manager on Hwy. 46 wanted to know more about their customers. She decides to focus on two variables: the average ticket spent by customers, and whether customers would consider purchasing ice cream if it was available. She interviewed 54 customers over a two-week period. Results of her research showed average ticket was $10.89 with a standard deviation of $2.35. Twenty-two customers said they would purchase ice cream if it was available.
a. Construct a 95% confidence
b. Construct a 90% confidence interval estimate for the population proportion of customers who would consider purchasing ice cream.
Assume the store manager wants to conduct a similar survey at the National Road store. Answer the following questions:
c. What
d. How many customers need to be selected to have 90% confidence of estimating the population proportion who would consider purchasing ice cream plus/minus 0.10 (10%)?
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