00:01
For part a, we have that the best point estimate that we can have for the average gas usage of all houses in the area is going to be our sample mean value.
00:18
So the sample mean value here, we find by taking the sum of our data points, 103 plus 156, plus 118, plus 89, plus 125, plus 147, plus 122, plus 109, plus 138, plus 99, and then dividing by 156, plus 186, plus 188, plus 847, and then dividing by, the number of data points, so we divide by 10.
00:37
So we would have that our best point estimate for the population mean value is going to be 120 .6.
00:46
Then for part b, our best estimate for, now i'm not sure what symbol that's supposed to be, it looks maybe like t or tau.
00:56
Our best estimate for tau is simply going to be 10 ,000 times our best point estimate for mu j.
01:06
So this is going to be approximately 10 ,000 times 120 .6, which gives us a result of, let's see here, 10 ,000 times that.
01:18
Oh, let's see, 10 ,000 times 120 .6, and it's insisting on giving me the scientific notation.
01:28
Okay, so that would be approximately 1 ,206 ,000.
01:35
Then moving on to part c, we're looking for the proportion of all houses that used at least 100 therms.
01:47
So we can estimate that population proportion, again using our sample proportion.
01:53
And we can see that out of the houses, let's see here.
01:58
So that is that used at least 100.
02:02
So we have one, two, three, four, five, six, seven, eight.
02:07
So our best point estimate would be that about 80%, our 0 .8, or a proportion of 0 .8, used at least 100 terms...
