9.19 Hypothesis testing of single mean and single proportion:

Rebecca and Matt are 14 year old twins. Matt’s height is 2 standard deviations below the mean for 14 year old boys’ height. Rebecca’s height is 0.10 standard deviations above the mean for 14 year old girls’ height. Interpret this.

• A Matt is 2.1 inches shorter than Rebecca
• B Rebecca is very tall compared to other 14 year old girls.
• C Rebecca is taller than Matt.
• D Matt is shorter than the average 14 year old boy.

Construct a histogram of the IPO data (see Table of Contents, 14. Appendix, Data Sets). Use 5 intervals.

Calculate the sample mean (a), the sample standard deviation (b) and the percent of the estimates that fall at or below 4 (c).

Calculate the median, M, the first quartile, Q1, the third quartile, Q3. Then construct a boxplot of the data.

The middle 50% of the data are between _____ and _____.

Find the probability that one randomly chosen child is in the 6th grade and prefers fried shrimp.

• A $\frac{\text{32}}{\text{70}}$
• B $\frac{8}{\text{32}}$
• C $\frac{8}{8}$
• D $\frac{8}{\text{70}}$

Find the probability that a child does not prefer pizza.

• A $\frac{\text{30}}{\text{70}}$
• B $\frac{\text{30}}{\text{40}}$
• C $\frac{\text{40}}{\text{70}}$
• D 1

Find the probability a child is in the 5th grade given that the child prefers spaghetti.

• A $\frac{9}{\text{19}}$
• B $\frac{9}{\text{70}}$
• C $\frac{9}{\text{30}}$
• D $\frac{\text{19}}{\text{70}}$

A sample of convenience is a random sample.

• A true
• B false

A statistic is a number that is a property of the population.

• A true
• B false

You should always throw out any data that are outliers.

• A true
• B false

Lee bakes pies for a small restaurant in Felton, CA. She generally bakes 20 pies in a day, on the average. Of interest is the num.ber of pies she bakes each day

• a Define the Random Variable $X$ .
• b State the distribution for $X$ .
• c Find the probability that Lee bakes more than 25 pies in any given day.

Six different brands of Italian salad dressing were randomly selected at a supermarket. The grams of fat per serving are 7, 7, 9, 6, 8, 5. Assume that the underlying distribution is normal. Calculate a 95% confidence interval for the population mean grams of fat per serving of Italian salad dressing sold in supermarkets.

Given: uniform, exponential, normal distributions. Match each to a statement below.

• a mean = median ≠ mode
• b mean>median>mode
• c mean = median = mode