Question

1) Is the following study design an anecdote, experiment, or observational study?

You'd like to investigate if what color shirt fans wear to a game help the Le Moyne Women's Soccer team score goals? You attend every home game. You write down how many fans attended the game, what color shirt they wore, and how many goals the soccer team scored.

2) Among the 268 words in the Gettysburg Address, 99 contain at least 5 letters. Is 99/268 = .369 a statistic, a parameter, or neither?

3) If you calculate the average number of hours that students in your class slept last night, describe (in words) the corresponding parameter of interest.

The parameter of interest is the average number of hours that  students slept last night.

4) If the mean of a distribution is 75 and the standard deviation is 9, how many standard deviations above the mean is 120?

5) A 1999 Gallup survey of a random sample of 1005 adult Americans found that 69% planned to give out Halloween treats from the door of their home. Does this finding necessarily prove that 69% of all adult Americans planned to give out treats? (yes/no)

6) I have a 3/5 = .60 probability of winning a game of solitaire.

How many games do I have to play before I can use the CLT to reasonably approximate the sampling distribution of the sample proportion of wins?

7) Suppose author A and Author B are doing studies on the same variable. Author A collects a sample of size 50 and Author B collects a sample of size 200. It turns out they both happen to get identical sample statistics. They then both construct 95% confidence intervals. Who has the smaller confidence interval? (A/B)

8) As sample size increases, the standard deviation (increases/decreases/stays the same)

Answer 1

2)

Among the 268 words in the Gettysburg Address, 99 contain at least 5 letters. Is 99/268 = .369

it is a parameter

..............

3)

The parameter of interest is the average number of hours that  students slept last night.

...........

4)

µ=   75
σ=   9
x = 120

75 + 9*a = 120

9*a = 45

a =5

so, 120 is 5 std dev above the mean

.................

5)

NO

.................

7)

Increasing the sample size decreases the width of confidence intervals

so, B will have smaller CI

................

8)

As sample size increases, the standard deviation DECREASES

.........................

Please revert back in case of any doubt.

Please upvote. Thanks in advance.