Answer:
Confidence interval for the population mean lifetime of the Amazon Kindle DX is (33.30 months to 42.70 months)
Step-by-step explanation:
Given;
Mean lifespan x = 38 months
Standard deviation r = 12 months
Number of kindle selected n = 25
Confidence range = 95%
Z*(95%) = 1.96
Confidence interval = x+/-Z*(r/√n)
= 38 +/- 1.96(12/√25)
= 38 +/- 4.70
Confidence interval = (33.30 months to 42.70 months)
Answer:

Step-by-step explanation:
3 minutes 59.1 seconds = (3*60) + 59.1 seconds = 180 + 59.1 seconds
=> 239.1 seconds
![\rule[225]{225}{2}](https://tex.z-dn.net/?f=%5Crule%5B225%5D%7B225%7D%7B2%7D)
4 minutes 3.8 seconds = (4*60) + 3.8 seconds = 240 + 3.8 seconds
=> 243.8 seconds
![\rule[225]{225}{2}](https://tex.z-dn.net/?f=%5Crule%5B225%5D%7B225%7D%7B2%7D)
4 minutes 1.6 seconds = (4*60) + 1.6 seconds = 240 + 1.6 seconds
=> 241.6 seconds
![\rule[225]{225}{2}](https://tex.z-dn.net/?f=%5Crule%5B225%5D%7B225%7D%7B2%7D)
Mean = Sum of data / No. of Data
Mean = 239.1 + 243.8 + 241.6 / 3
Mean = 724.5 / 3
Mean = 241.5 seconds
<u>In Minutes and Seconds:</u>
= 241.5 / 60 = 4.025 minutes
= 4 minutes + 0.025 minutes
= 4 minutes + (0.025 * 60) seconds
= 4 minutes 1.5 seconds
![\rule[225]{225}{2}](https://tex.z-dn.net/?f=%5Crule%5B225%5D%7B225%7D%7B2%7D)
Hope this helped!
<h3>
~AH1807</h3>
Answer:
X/4 = 2
X=8
8 divided by 4 is 2 and 4x2 is 8