We think that our average customer spends roughly $40 - $60 every time he/she visits our website. We can assume that the expenditure amounts are normally distributed, but, we do not know the standard deviation. We sample 15 web expenditures; our sample average is $52 and our sample standard deviation is $8.

We are 95% sure that our true population average is $52 plus or minus....

What is the range of the numbers in the list above?

(1) .

(2) .

Our final sales figures (in millions) for the year are:

Use Excel to calculate the correlation coefficient between the month number

etc.

and the sales figure(s).

Also, compute the value for testing the confidence level for the correlation coefficient.

Our final sales figures (in millions) for the year are:

Using the above data, calculate the regression line

that best fits the data.

Hint – make the month number

etc.

the independent variable and make the sales figure the dependent variable . Use Excel to calculate the slope.

We are trying to determine the average age of the Cardinal baseball fan. We know that the age distribution of Cardinal nation is normally distributed with a standard deviation of 20. We need to determine the average age. We take a sample of 40 fans and the average of our sample is 42 years old.

What is the 95% confidence interval (range) for our sample average of 42? (remember – confidence intervals are always 2- tailed (plus or minus)).

We randomly sampled 175 people in Our Town USA and found that 62.9% of them favored Coke over Pepsi. We decided on a 90% 2 tailed test (z=1.64) and proclaimed that we were 90% confident of the 62.9% plus or minus 6%.

We arrived at the 6% by first calculating the standard deviation:

and then multiplying .0365 by z (1.64)

What sample size do we need to be plus or minus 4%?

We are trying to determine the average age of the Cardinal baseball fan. We know that the age distribution of Cardinal nation is normally distributed with a standard deviation of 20. We need to determine the average age. We take a sample of 40 fans and the average of our sample is 42 years old.

However, the Cardinal President of Operations wants a 98% confidence interval of plus or minus 5.0. What sample size do we need to satisfy his request?

A data set comprises 1,000 entries. What is its interquartile range?

Statement 1: The 75th percentile is 64.

Statement 2: The 25th percentile is 30.

The average sales price of a home in Ourtown U.S.A. is $120,000.

The population standard deviation is $20,000.

What is the probability that the next home will sell for more than $130,000?

Seven kids in a kindergarten class have the following ages:

.

Amy and Lilly join this kindergarten class. What is the range of the nine kids' ages?

(1) Amy is years old.

(2) The sum of the ages of both kids is .