Questions from Statistics Principles

Q: Refer to Exercise 5.7. Suppose that for each purchase

Refer to Exercise 5.7. Suppose that for each purchase P(B) = ½ and the decisions in different weeks are independent. Assign probabilities to the elementary outcomes and obtain the distribution of X....

Q: Students are asked about the number of songs they downloaded from a

Students are asked about the number of songs they downloaded from a pay-for-songs Web site the last month. From a random sample of 39 students, the sample mean was 4. 7 with a standard deviation of 3....

Q: The freshness of produce at a superstore is rated on a scale

The freshness of produce at a superstore is rated on a scale of 1 to 5 with 5 being very fresh . From a random sample of 49 customers, the average score was 3.8 with a standard deviation of .7. (a) Ob...

Q: A researcher asked participants to wear a simple counting device for a

A researcher asked participants to wear a simple counting device for a week and they counted the number of times that they thought about food. Determine a point estimate of the daily mean number of ti...

Q: Referring to Example, where the 158 times to complete the firefighter

Referring to Example, where the 158 times to complete the firefighter test have mean 307. 77 and standard deviation 51.852, obtain a 99% confidence interval for the mean time of all possible recruits...

Q: Based on a survey of 140 employed persons in a city,

Based on a survey of 140 employed persons in a city, the mean and standard deviation of the commuting distances between home and the principal place of business are found to be 8.6 and 4.3 miles, resp...

Q: The weekly flier from a large box store always features many items

The weekly flier from a large box store always features many items having a mail-in rebate. A random sample of 50 submissions produced the summary statistics x = 43 and s = 7.7 days for the time inter...

Q: A credit company randomly selected 50 contested items and recorded the dollar

A credit company randomly selected 50 contested items and recorded the dollar amount being contested. These contested items h ad a sample mean x = 95.74 dollars and s = 24.63 dollars. Construct a 95%...

Q: In a study to determine whether a certain stimulant produces hyperactivity,

In a study to determine whether a certain stimulant produces hyperactivity, 44 mice were injected with 10 micrograms of the stimulant. Afterward, each mouse was given a hyperactivity rating score. The...

Q: Refer to the Statistics in the stiffness of lumber. A computer

Refer to the Statistics in the stiffness of lumber. A computer calculation gives x = 1.596 and s = .3872 for the n = 100 measurements of stiffness. Find a 95% confidence interval for the mean stiffnes...