The marks of candidates in Mathematics and English in 2009 were represented by the independent random variables $X$ and $Y$ with distributions $N\left( {28,{\text{ }}{{5.6}^2}} \right)$ and $N\left( {52,{\text{ }}{{12.4}^2}} \right)$ respectively. Each candidate’s marks were combined to give a final mark $F$, where $F = X + \frac{1}{2}Y$.
a) Find $E\left( F \right)$ and $Var\left( F \right)$.
b) The final marks of a random sample of 10 candidates from Grinford in 2009 had a mean of 49. Test at the 5% significance level whether this result suggests that the mean final mark of all candidates from Grinford in 2009 was lower than elsewhere.
پاسخ تشریحی :
تحلیل ویدئویی تست
تحلیل ویدئویی برای این تست ثبت نشده است!
محتواهای آموزشی مشابه
فایل های پاورپوینت، ویدئو، صوتی، متنی و ...
پرسش و پاسخ های مشابه
سوال کنید یا به سوالات دیگران پاسخ دهید ...