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Use the amounts of money grossed by movies with ratings of PG or PG-13 as sample

ID: 3229355 • Letter: U

Question

Use the amounts of money grossed by movies with ratings of PG or PG-13 as sample one, and use the amounts of money grossed by movies with R ratings as sample two. Complete parts (a) and (b). Assume that the two samples are independent simple random samples selected from normally distributed populations. Do not assume that the population standard deviations are equal.

A. use a .01 sig level to test the claim that movies with raing of pg or pg13 have a higher mean gross amount thatn moveis with R rating s (Reject or fail to reject H0. there (is or is not) sufficient evidence.

B.Construct a 99%confidence interval estimate of the difference between the mean amount of money grossed by movies with ratings of PG or PG-13 and the mean amount of money grossed by movies with R ratings. 2 decimal place

What does the confidence interval suggest about movies as an investmen

MPAA Rating Gross ($) in Millions R 117 R 78 PG-13 101 PG-13 66 PG-13 121 PG-13 119 PG-13 101 R 100 R 55 PG 104 PG-13 213 R 74 PG 13 PG-13 290 R 47 R 10 R 111 PG-13 100 PG-13 303 PG-13 19 PG-13 112 PG-13 48 PG-13 228 R 83 PG 17 PG-13 371 PG-13 300 PG-13 118 R 33 PG-13 114 PG-13 120 R 101 PG-13 120 PG-13 234 R 209

Explanation / Answer

We perform the t-test in R software.

> t.test(tt$Millions[tt$Rating=="R"],tt$Millions[tt$Rating=="PG-13" | tt$Rating=="PG"],alternative="greater",level=0.01,var.equal=TRUE)

        Two Sample t-test

data: tt$Millions[tt$Rating == "R"] and tt$Millions[tt$Rating == "PG-13" | tt$Rating == "PG"]
t = -1.9482, df = 33, p-value = 0.97
alternative hypothesis: true difference in means is greater than 0
95 percent confidence interval:
-112.1881       Inf
sample estimates:
mean of x mean of y
84.83333 144.86957

A. use a .01 sig level to test the claim that movies with raing of pg or pg13 have a higher mean gross amount thatn moveis with R rating s (Reject or fail to reject H0. there (is or is not) sufficient evidence.

At 0.01 significance level, the mean of PG-13 or PG is not higher than R rated movies.

B.Construct a 99%confidence interval estimate of the difference between the mean amount of money grossed by movies with ratings of PG or PG-13 and the mean amount of money grossed by movies with R ratings. 2 decimal place

What does the confidence interval suggest about movies as an investmen

The 99% CI is ( -112.1881, Inf) which contains the mean difference of -1.948, and hence the difference is insignificant.