Consider the following results for two independent random samples taken from two populations. Sample 1 Sample 2
n1=50 n2=35
x¯1=13.6 x¯2=11.6
σ1=2.2 σ2=3.0

Required:
a. What is the point estimate of the difference between the two population means?
b. Provide a 90% confidence interval for the difference between the two population means.
c. Provide a 95% confidence interval for the difference between the two population means.

a. 2

b. The 90% confidence interval for the difference between the two population means is (1.02, 2.98).

c. The 95% confidence interval for the difference between the two population means is (0.83, 3.17).

Step-by-step explanation:

Before solving this question, we need to understand the central limit theorem and the subtraction of normal variables.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean and standard deviation , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean and standard deviation .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

Subtraction between normal variables:

When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.

Sample 1:

Sample 2:

Distribution of the difference:

a. What is the point estimate of the difference between the two population means?

Sample difference, so

b. Provide a 90% confidence interval for the difference between the two population means.

We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Z-table as such z has a p-value of .

That is z with a pvalue of , so Z = 1.645.

The margin of error is:

The lower end of the interval is the sample mean subtracted by M. So it is 2 - 0.98 = 1.02

The upper end of the interval is the sample mean added to M. So it is 2 + 0.98 = 2.98

The 90% confidence interval for the difference between the two population means is (1.02, 2.98).

c. Provide a 95% confidence interval for the difference between the two population means.

Following the same logic as b., we have that . So

The lower end of the interval is the sample mean subtracted by M. So it is 2 - 1.17 = 0.83

The upper end of the interval is the sample mean added to M. So it is 2 + 1.17 = 3.17

The 95% confidence interval for the difference between the two population means is (0.83, 3.17).

javeir earned 56 dollors more than kyle so kyle and javier had 14w but javier made 56 dollors more so 14w plus 56 equals 70w so kyle has 14w

step-by-step explanation: hope i plz give me brainliest with the points so this is not constant cause it says last week so its clearly not every week