Independent random samples were selected from two...

Independent random samples were selected from two quantitative populations, with sample sizes, means, and variances given below. Population 1 2 Sample Size 39 46 Sample Mean 9.5 7.3 Sample Variance 8.89 14.32 Construct a 90% confidence interval for the difference in the population means. (Use ?1 - ?2. Round your answers to two decimal places.) to Construct a 99% confidence interval for the difference in the population means. (Round your answers to two decimal places.) to

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Transcript

00:01 See that you need help with this question, and it says, independent random samples were selected from two quantitative populations.

00:08 The sample sizes, means, and variances given below.

00:12 Construct a 90 % confidence interval for the difference in the population means.

00:18 So for the sample, the first thing that you have to do is you have to calculate the sample standard deviation.

00:29 So you have to combine the sample standard deviations.

00:34 So you have to find the sample standard deviations from the sample variance.

00:40 So you're going to get 2 .98 and 3 .78.

00:46 And i just rounded those to the 100th place.

00:49 So you're going to take the square root of 2 .98 squared over 39 plus 3 .78 squared over 46.

01:01 And that's going to equal the square root of 0 .54.

01:06 And that's going to equal 0 .73.

01:09 So we're going to end up using that later in our problem.

01:15 Then what we're going to do is we need to calculate our degrees of freedom.

01:18 That's important for when we're going to calculate our t score.

01:22 So we're going to take 2 .98 squared, divide that by 39, and we're going to add that to 3 .78.

01:32 We're going to square that, and we're going to put that over 46...

Question

Please give Ace some feedback