The National Football League (NFL) polls fans to develop a rating for each football game. Each game is rated on a scale from 0 (forgettable) to 100 (memorable). The fan ratings for a random sample of 12 games follow. 57 61 87 74 72 73 19 56 81 79 83 75 a. Develop a point estimate of mean fan rating for the population of NFL games (to 2 decimals). b. Develop a point estimate of the standard deviation for the population of NFL games (to 4 decimals).

Respuesta :

Answer:

a. The estimate of  mean  fan rating for the population of NFL games=68.08

b. The estimate of standard deviation=18.8785

Step-by-step explanation:

Given

The fan ratings for a random sample of 12 games follow:

57, 61, 87,74,72,73,19,56,81,79,83 and 75

a.Mean =[tex] \frac{ sum\;of\;data}{ total\;number \; of data}[/tex]

Mean=[tex]\frac{57+61+87+74+72+73+19+56+81+79+83+75}{12}[/tex]

Mean= 68.08

b.[tex]\mid x-\bar x\mid[/tex]                                    [tex]{\mid x-\bar x\mid}^2[/tex]

11.08                                                122.7664

7.08                                                 50.1264

18.92                                                357.9664

5.92                                                 35.0464

3.92                                                  15.3664

4.92                                                  72.6192

49.08                                                2408.8464

12.08                                                 145.9264

12.92                                                  166.9264

10.92                                                  119.2464

14.92                                                   734.064

6.92                                                    47.8864

Standard deviation=[tex]{\sqrt\frac{\sum{\mid x-\bar x\mid}^2}{n}[/tex]

n=12

[tex]\sum{\mid x-\bar x\mid}^2=4276.7872[/tex]

Standard deviation=[tex]\sqrt\frac{4276.7872}{12}[/tex]

Standard deviation=[tex]\sqrt{356.3989}[/tex]

Standard deviation = 18.8785

The estimate of the standard deviation for the population of NFL games=18.8785

The point estimates for the mean and standard deviation of the given data is respectively; 68 and 17.6

What is point Estimate?

A) To find the point estimate of the mean, we add all up all the data and divide by the number of values.

Thus;

∑x = 57 + 61 + 86 + 87 + 72 + 73 + 19 + 56 + 81 + 79 + 83 + 75 = 816

n = 12 numbers

Thus;

mean = ∑x/n = 816/12

Mean = 68

B) To find the estimate of the standard deviation, we would get it from the formula;

s = √[(n*(∑x²) - (∑x)²)/n(n - 1)]

∑x² = 572 + 612 + 862 + ... + 742 = 59,010

s = √[ (12*(59,010) - (816)²)/(12)(11)]

s = 17.6

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