Question

A sample of 25 undergraduates reported the following dollar amounts of entertainment expenses last year:

Answer 1

Answer:

A.

mean = 724.2

Median = 715

Mode = 768

B.

Range = 85

Standard deviation = 29.30

C.

Interval = [665.6, 782.8]

Step-by-step explanation:

Number of samples n = 25

Summation X= 769 + 691 + 699 +730+711+ 765+ 702 718 +719 +712+ 768 +688 +757+695 768 +735 +709 +758 +708+ 693 +736 700+ 687 +772 +715 = 18105

A.

1. Mean = 18105/25

= 724.2

2. Median is the middle value when arranged from the least value to the highest = 715

3. Mode is the number with the highest frequency = 768 (occured two times)

B.

1. Range = highest value - lowest value

Highest value = 772

Lowest value = 687

772-687 = 85

2. Standard deviation = √(X-barX)²/n-1

= √20604/25-1

=√858.5

= 29.30

Please check attachment for the full calculation of the standard deviation

C.

Interval

[Mean - 2(sd), mean + 2(sd)]

= [724.2-2x29.3, 724.2+2x29.3]

=[665.6, 782.8]