A researcher is interested in estimating the mean time it takes adults to learn a certain task. He wants to be 99% confident that the mean time for a sample of adults is within 1.5 minutes of μ. In a small pilot study, the standard deviation of learning times was 8.2 minutes. How large a sample of adults should be tested? Hint: Make sure that you round up to the next integer.

Q: The data set has size 60. Approximately how many observations lie within three standard deviations…

A: From the empirical rule

Q: Suppose your statistics professor graded your test with a Z Score.  You earned a 3.25 on a test with…

A: Answer:- Given, Mean, µ = 71  Standard deviation, σ = 8  And Z-score = 3.25  We need to find the…

Q: Identify the data value corresponding to the indicated percentile. The amount of sleep an adult gets…

A: Let us define the random variable X as the amount of sleep an adult gets per day is normally…

Q: A person scores 81 on a test of verbal ability and 6.4 on a test of quantitative ability. for the…

A: Consider X is a random variable defined as the score of the verbal ability test of a person.Consider…

Q: Ms. Hammell's Algebra 2 students took an exam. the results showed a mean of 78, with a standard…

A: The normal distribution is the most useful theoretical distribution for continuous variables.…

Q: You are interested in determining the mean amount of dollars that employees at your company spend on…

A: Solution: From the given information, confidence level is 0.90, σ=1 and E=300.

Q: Overweight Men For a random sample of 60 overweight men, the mean of the number of pounds that they…

A: From the provided information, Sample size (n) = 60 Sample mean (x̄) = 31 pounds Standard deviation…

Q: A class of 150 students took a final exam in mathematics. The mean score was 72% and the standard…

A: Here, µ = 72%, σ = 14%, and n = 150.

Q: SAT scores have a mean of 1026 and a standard deviation of 209. ACT scores have a mean of 20.8 and a…

A:

Q: recent awards​ ceremony, the age of the winner for best actor was 33 and the age of the winner for…

A: Given that  For all best​ actors, the mean age is 44.6 years and the standard deviation is 8.3…

Q: A successful basketball player has a height of 6 feet 6 ​inches, or 198 cm. Based on statistics from…

A:

Q: On a verbal skill test, the mean was 72 and the standard deviation was 7. If John scored 75, what…

A: Given data,Mean μ=72sd      σ=7If John scored 75z-score=?

Q: Use z scores to compare the given values. ages are dotards ceremony, the age of the winner for best…

A:

Q: Find the indicated IQ score.

A: Let X denote the IQ scores of adults. Given that X follows N(mean = 100, SD = 15)

Q: 0.75

A: Given X is normal Distributed with mean µ = 100.0 and standard deviation σ = 15.0 now will use…

Q: Find the indicated IQ score. The graph to the right depicts IQ scores of adults, and those scores…

A: GIVEN DATA  normal distribution  μ=100σ =15 area to the right of x = 0.55 x = ?

Q: Brian scored an 80% on a Chemistry Exam. The average on the exam was a 68%, with a standard…

A:

Q: A successful basketball player has a height of 6 feet 11 ​inches, or 211 cm. Based on statistics…

A:

Q: Use z scores to compare the given values.   In a recent awards​ ceremony, the age of the winner for…

A: The Z-score of a random variable X is defined as follows: Z = (X – µ)/σ. Here, µ and σ are the mean…

Q: The data set has size 80. Approximately how many observations lie within two standard deviations to…

A: Empirical rule: On a normal distribution about 68% of data will be within one standard deviation of…

Q: Find the indicated IQ score. The graph to the right depicts IQ scores of adults, and those scores…

A: Given, mean, μ = 100Standard deviation, σ = 15Let X be a random variable represents the IQ score of…