Happy is four times as old as Grumpy. The sum of their age is 100. How old are Happy and Grumpy?

If 49 cars are lined up and extend 528 feet, what would the average length per car be, assuming they are bumper-to-bumper? The result can be calculated as follows: we know the number of cars (49) and the total length (528 feet). Therefore, the average length is calculated as 528 feet divided by 49, which gives an average length of about 10.78 feet.

The 99% confidence interval for the actual mean difference between average mail-order and internet purchase amounts falls within [$(-31.82), $12.02].

Step-by-step clarification:

We know a random sample of 16 mail-order sales receipts shows a mean sale amount of $74.50 and a standard deviation of $17.25.

For internet sales, a random sample of 9 receipts gives a mean sale amount of $84.40 with a standard deviation of $21.25.

The pivotal value utilized for constructing a 99% confidence interval for the true mean difference is given by;

                      P.Q.  =  

 ~

where,

= sample mean of mail-order sales = $74.50

= sample mean of internet sales = $84.40

= standard deviation for mail-order sales = $17.25

= standard deviation for internet sales = $21.25

= number of mail-order sales receipts = 16

= number of internet sales receipts = 9

Furthermore,  

 =   = 18.74

The actual mean difference between average mail-order and internet purchases is denoted by (

).

Thus, the 99% confidence interval for () is expressed as;

      = Here, the t critical value at the 0.5% significance level with 23 degrees of freedom is 2.807.           =

          = [$-31.82, $12.02]

Therefore, the 99% confidence interval for the true mean difference between average mail-order and internet purchases is [$(-31.82), $12.02].

Answer:

2/5

Step-by-step explanation:

By subtracting 130, 35, and 74 from the total of 400, you arrive at 160 left. Next, simplify this fraction by finding the greatest common divisor to get 2/5!