Question

***PLEASE ANSWER ALL QUESTIONS***

Question 6 (1 point)

Suppose that the probability of a baseball player getting a hit in an at-bat is 0.284. If the player has 38 at-bats during a week, what's the probability that he gets no more than 11 hits?

Question 6 options:

1)

0.1411

2)

0.4686

3)

0.0706

4)

0.3903

5)

0.6097

Question 7 (1 point)

196 employees of your firm were asked about their job satisfaction. Out of the 196, 29 said they were unsatisfied. What is the estimate of the population proportion? What is the standard error of this estimate?

Question 7 options:

1)	Estimate of proportion: 0.148, Standard error: 0.0018.

2)	Estimate of proportion: 0.852, Standard error: 0.0018.

3)	Estimate of proportion: 0.148, Standard error: 0.0254.

4)	Estimate of proportion: 0.852, Standard error: 0.0254.

5)	The true population proportion is needed to calculate this.

Question 10 (1 point)

The owner of a local supermarket believes the average number of gallons of milk the store sells per day is 311.2. In a random sample of 22 days, the owner finds that the average number of gallons sold was 281.3 with a standard deviation of 30.12. Using this information, the owner calculated the confidence interval of (270.3, 292.3) with a confidence level of 90%. Which of the following statements is the best conclusion?

Question 10 options:

1)	We are 90% confident that the average number of gallons sold per day is less than 311.2.

2)	The average number of gallons sold per day is not signficantly different from 311.2.

3)	The percentage of days on which more than 311.2 gallons of milk are sold is 90%.

4)	We are 90% confident that the average number of gallons sold per day is greater than 311.2.

5)	We cannot determine the proper interpretation based on the information given.

Question 11 (1 point)

A restaurant wants to test a new in-store marketing scheme in a small number of stores before rolling it out nationwide. The new ad promotes a premium drink that they want to increase the sales of. 12 locations are chosen at random and the number of drinks sold are recorded for 2 months before the new ad campaign and 2 months after. The average difference in nationwide sales quantity before the ad campaign to after (after - before) is 0.5 with a standard deviation of 9.41. Using this information, they calculate a 90% confidence paired-t interval of (-4.38, 5.38). Which of the following is the best interpretation?

Question 11 options:

1)	We are 90% confident that the difference between the average sales after the ad campaign and the average sales before the ad campaign is between -4.38 and 5.38.

2)	We are 90% confident that the average difference in the sales quantity after to before of the stores sampled is between -4.38 and 5.38.

3)	We are 90% confident that the average difference in sales quantity between after the ad campaign to before for all restaurants is between -4.38 and 5.38.

4)	We are certain the average difference in sales quantity between after the ad campaign to before for all stores is between -4.38 and 5.38.

5)	The proportion of all stores that had a difference in sales between after the ad campaign to before is 90%.

Answer 1

6)

here this is binomial with parameter n=38 and p=0.284

P(X<=11)=

∑x=0a     (nCx)px(1−p)(n-x)    =

0.6097

7)

sample success x =		29
sample size          n=		196
sample proportion p̂ =x/n=		0.1480
std error se= √(p*(1-p)/n) =		0.0254

Estimate of proportion: 0.148, Standard error: 0.0254.

10)

We are 90% confident that the average number of gallons sold per day is less than 311.2..(since it is not in confidence interval)

11)3rd option

We are 90% confident that the average difference in sales quantity between after the ad campaign to before for all restaurants is between -4.38 and 5.38.