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University of Pittsburgh - STAT 0200 CH 3 1)Using the 68-95-99

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University of Pittsburgh - STAT 0200

CH 3

1)Using the 68-95-99.7 rule, what percentage of students score below 62?

 

 

 

2. Using the standard Normal distribution tables, the area under the standard Normal curve corresponding to Z > –1.62 is what? Sketch the standardized curve and find the area.

 

 

3. The proportion of infants with birth weights above 125 oz is

µ = 110 oz; sigma = 15 oz.; x = 125 oz.

 

4. The proportion of infants with birth weights between 125 oz and 140 oz is

µ = 110 oz; sigma = 15 oz.; x₁ = 125 oz.; x₂ = 140.

 

 

CH 11

 

1. The incomes in a certain large population of college teachers have a normal distribution with mean $75,000 and standard deviation $10,000. Four teachers are selected at random from this population to serve on a committee. What is the probability that their average salary is less than $65,000?

 

 

2. The central limit theorem says that when a simple sample of size n is drawn from any population with mean μ and standard deviation σ, then when n is sufficiently large

 

 

3. Which of the following statements is true with respect to the sampling distribution of the sample mean, x bar ?

 

 

4. How many bags should be selected so that the standard deviation of the sample mean is 0.1 ounces?

σ = 1.0

n = ?

 

 

 

 

 

 

 

5. If 100 bags of cookies are selected randomly, the probability that the sample mean will be between 14.9 and 15.1 ounces is

 

 

 

CH 14

 

1. A researcher selects a random sample. A 90% confidence interval for a population mean μ

 

 

2. The margin of error associated with a 90% confidence interval for the researcher’s 90% confidence interval for μ is

 

 

 

CH 15

 

1. Is the mean age at which American children can first read now under 4 years? If the population of all American children has mean age of μ years until they begin to read and standard deviation σ years, what are the null and alternative hypotheses to research this?

 

 

2. The P-value for this test is

 

 

3. Based on the P-value computed in problem 21 above,

 

4. If the researcher deems the data to be statistically significant, which of the following is true with respect to a conclusion reached?