The sum of arithmetic series is given by:
Sn=n/2(a1+an)
where:
n=number of terms
a1=first term
an=nth term
but
n=18, an=275, Sn=4185
plugging the values in the formula we get:
4185=18/2(a1+275)
simplifying this we get:
4185=9(a1+275)
dividing through by 9 we get:
465=a1+275
thus
a1=465-275
a1=190
Answer: first number is 190
Answer:hrhdhf end b
Step-by-step explanation:
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Answer:
Step-by-step explanation:
Hello!
a)
The dependent variable is
Y: length of a dugong
The explanatory variable is
X: age of a dugong
You need to estimate the linear regression of the length of the dugongs as a function of their age.
Using the given data I've estimated the regression using a statistic software:
The regression model is E(Yi)= α + βXi
The estimated model is ^Yi= a + bXi
Where a is the estimate of the intercept and b is the estimate of the slope:
a= 2.02
b= 0.03
And the estimate of the population variance of the error is Se²= 0.03
The estimated regression equation is ^Yi= 2.02 + 0.03Xi
b)
You have to estimate the length of a dugong when its age is 11 years using the model, for this all you have to do is replace X=11 in the regression line and calculate the corresponding ^Y value:
^Yi= 2.02 + 0.03*11= 2.35
The average length of an 11-year-old dugong should be 2.35.
I hope it helps!
