00:01
So we want to use our equation and we have 12 pieces of data and predict, find what the, predict what the mean weight would be if the length of the bear is 154 .5 centimeters.
00:15
So plugging that into the regression equation, and i'm not going to show you the coefficients, but plugging it into my model, my calculator, i get 119 .278 and that would be kilograms.
00:28
And i'm going to store that as alpha a in my calculator.
00:32
Now in part b we want to find a 95 % confidence interval for the mean weight of black bears that are this long.
00:41
And so we will have that 119 .2, 119 .278 plus or minus, and we need a t value with .025 in the upper tail and 11 degrees of freedom.
00:55
And that value corresponds to 2 .201.
01:00
Now we need to multiply that by the standard, the standard deviation of the error or the residuals.
01:06
And i have that for my software being 20 .8577.
01:12
And now we need to multiply that by the square root of 1 over the sample size plus we'll take that evaluating number 154 .5 minus the mean of the x's.
01:25
And i have the mean of the x's to be 142 .875.
01:31
And then that quantity is squared...