Question

(PLEASE TYPE THE ANSWERS) (STATISTICS 500)

In a large clinical​ trial, 390 comma 827390,827 children were randomly assigned to two groups. The treatment group consisted of 194 comma 857194,857 children given a vaccine for a certain​disease, and 3030 of those children developed the disease. The other 195 comma 970195,970 children were given a​ placebo, and 9494 of those children developed the disease. Consider the vaccine treatment group to be the first sample. Complete parts​ (a) through​ (d) below

a. Assume that a

0.050.05

significance level will be used to test the claim that

p 1p1less than<p 2p2.

Which is​ better: A hypothesis test or a confidence​ interval?

▼

A confidence interval

A hypothesis test

is better.

b. In​ general, when dealing with inferences for two population​ proportions, which two of the following are​ equivalent: confidence interval​ method; P-value​ method; critical value​ method?

▼

Confidence interval method and critical value methodConfidence interval method and critical value method

Confidence interval method and Upper P dash value methodConfidence interval method and P-value method

Upper P dash value method and critical value methodP-value method and critical value method

are​ equivalent, in that they will always lead to the same conclusion. Both of these methods use a standard deviation based on

▼

estimated values of the population proportions,

the assumption that the two population proportions are equal,

whereas the other method uses a standard deviation based on

▼

the assumption that the two population proportions are equal.

estimated values of the population proportions.

c. If a

0.050.05

significance level is to be used to test the claim that

p 1p1less than<p 2p2​,

what confidence level should be​ used?

nothing​%

​(Type an integer or a​ decimal.)

d. If the claim in part​ (c) is tested using this sample​ data, we get this confidence​ interval:

negative 0.000419−0.000419less than<p 1p1minus−p 2p2less than<negative 0.000232−0.000232.

What does this confidence interval suggest about the​ claim?

Because the confidence interval

▼

does not contain

contains

▼

0,

the critical value,

the significance level,

the pooled sample proportion,

there

▼

appears to be

does not appear to be

a significant difference between the two proportions. Because the confidence interval consists

▼

only of values less than

only of values greater than

of values both less than and greater than

▼

0,

the pooled sample proportion,

the significance level,

the critical value,

it appears that the first proportion is

▼

less than

greater than

not significantly different from

the second proportion. There is

▼

insufficient

sufficient

evidence to support the claim that the rate of polio is less for children given the vaccine than it is for children given a placebo.

Answer 1