Gallon he uses to and from work = (2 / 3) of 12
12 * (2 / 3)
= 8 ----- he uses 8 gallons to and from work
+ 2 additinal for errands
therefore gallons for work + gallons for errand = *8 + 2
= 10
your answer is 10
Answer:
true
Step-by-step explanation:
it shows that the students buy those pencils
Answer:
no...
Step-by-step explanation:
Using the t-distribution, the 90% confidence interval for the mean number of absences is given by: (9.22, 11.60).
<h3>What is a t-distribution confidence interval?</h3>
The confidence interval is:

In which:
is the sample mean.
- s is the standard deviation for the sample.
The critical value, using a t-distribution calculator, for a two-tailed 90% confidence interval, with 28 - 1 = 27 df, is t = 1.7033.
Researching this problem on the internet, the parameters are given by:
.
Hence the bounds of the interval are given by:
The 90% confidence interval for the mean number of absences is given by: (9.22, 11.60).
More can be learned about the t-distribution at brainly.com/question/16162795
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Answer: Mean = 4.8 and variance = 5.16
Step-by-step explanation:
Since we have given
Let X be the number of storms occur in next year
Y= 1 if the next year is good.
Y=2 if the next year is bad.
Mean for good year = 3
probability for good year = 0.4
Mean for bad year = 5
probability for bad year = 0.6
So, Expected value would be
![E[x]=\sum xp(x)\\\\=3\times 0.4+5\times 0.6\\\\=1.2+3\\=4.2](https://tex.z-dn.net/?f=E%5Bx%5D%3D%5Csum%20xp%28x%29%5C%5C%5C%5C%3D3%5Ctimes%200.4%2B5%5Ctimes%200.6%5C%5C%5C%5C%3D1.2%2B3%5C%5C%3D4.2)
Variance of the number of storms that will occur.
![Var[x]=E[x^2]-(E[x])^2](https://tex.z-dn.net/?f=Var%5Bx%5D%3DE%5Bx%5E2%5D-%28E%5Bx%5D%29%5E2)
![E[x^2]=E[x^2|Y=1].P(Y=1)+E[x^2|Y=2].P(Y=2)\\\\=(3+9)\times 0.4+(5+25)\times 0.6\\\\=12\times 0.4+30\times 0.6\\\\=4.8+18\\\\=22.8](https://tex.z-dn.net/?f=E%5Bx%5E2%5D%3DE%5Bx%5E2%7CY%3D1%5D.P%28Y%3D1%29%2BE%5Bx%5E2%7CY%3D2%5D.P%28Y%3D2%29%5C%5C%5C%5C%3D%283%2B9%29%5Ctimes%200.4%2B%285%2B25%29%5Ctimes%200.6%5C%5C%5C%5C%3D12%5Ctimes%200.4%2B30%5Ctimes%200.6%5C%5C%5C%5C%3D4.8%2B18%5C%5C%5C%5C%3D22.8)
So, Variance would be

Hence, Mean = 4.8 and variance = 5.16