Question

Private and public colleges and universities, including LSU, rely on money contributed by individuals, corporations, and foundations for both salaries and operating expenses. Much of this money is put into a fund called an endowment, and the college spends only the interest earned by the fund. A random sample of 9 college endowments drawn from the list of endowments in the Chronicle of Higher Education Almanac (2010) yielded the following statistics (in millions of dollars): Sample mean x = 1.32, and the sample standard deviation s = 0.90.

(a) Construct a 95% confidence interval of the unknown population mean

(b) Construct a 80% confidence interval of the population standard deviation.

Please explain why you use a t chart for a and chi square for b.

Answer 1

Date of the populctiomstended dleviction thoe the amplee populoukion nomaliy ton normdl sample fr Cn- we hawe r2i umbiased ejtin pepulaton vaincednd the 2 arel nomal b4tt

now t r eu becomer as ConRelante r-e. 8 о./o interved-of population 6.48 3.49o 13. 362 43491:8S67 This is onfilance inderUc Lourerlinut三0-4849 Upper

Date of the populctiomstended dleviction thoe the amplee populoukion nomaliy ton normdl sample fr Cn- we hawe r2i umbiased ejtin pepulaton vaincednd the 2 arel nomal b4tt

we have ns ㄧ一we have given-data -of-_g collo es endouom ent u is In Z2 such tha 2 but in this problern we nove ⑤ponder standard ㅡㅡㅡ levicetton--is- not thet is usually un enouon given ^ we wou Cnoto the populcion averaye and have no nでee

in prachi cul suwitthuction we Teplute the Howevec this subshitution changes Convereanse robubiuty ortunatel dle slredonveence leve by the nterved pat ng Xal32 S o.goos 322.30 6 Xo.g 1.32+_2. 306x013 2.0118 0 6268 S ofo Con Sica Fontlotion hedn ower imio 62 68