# business statistics discussion post 2

Your initial post should be 75-150 words in length.

Watch this video: https://www.youtube.com/watch?v=tFWsuO9f74o

• What is a confidence interval?
• What are some factors that affect the size of a confidence interval?
• In the discussion for week 4, you rolled a pair of dice 10 times and calculated the average sum of your rolls. Then you did the same thing with 20 rolls. Use your results from the week 4 discussion for the average of 10 rolls and for the average of 20 rolls to construct a 95% confidence interval for the true mean of the sum of a pair of dice (assume Ïƒ = 2.41).
• What do you notice about the length of the interval for the mean of 10 rolls versus the mean of 20 rolls? Did you expect this? Why or why not?
• Using your mean for 20 rolls, calculate the 90% confidence interval. Explain its size as compared to the 95% confidence interval for 20 rolls.

**Note below are the average sum of my rolls from my discussion for week 4. This information is needed to help answer question above.**

#### When rolling the dice 10 times, the results are shown below:

3+2=5
5+5=10
1+1=2
1+5=6
3+6=9
4+1=5
1+1=2
2+6=8
1+5=6
3+2=5
(Total avg: 58/10=5.8)

When rolling the dice 20 times, the results were as shown below:

1+2=3
1+3=4
6+4=10
2+1=3
6+1=7
1+3=4
6+5=11
1+6=7
1+2=3
4+1=5
6+2=8
2+2=4
3+2=5
3+3=6
1+6=7
5+2=7
2+1=3
3+3=6
2+2=4
1+5=6
(Total avg: 113/20=5.65)

Please provide original work. No plagiarizing.  