Question

Fertilizer: In an agricultural experiment, the effects of two fertilizers on the production of oranges were measured. Ten randomly selected plots of land were treated with fertilizer A, and 7 randomly selected plots were treated with fertilizer B. The number of pounds of harvested fruit was measured from each plot. Following are the results.

Fertilizer A
464	483	441	491	403
466	448	457	437	516

Fertilizer B
414	408	398	382	368
393	437

-Construct a 90% confidence interval for the difference between the mean yields for the two types of fertilizer. Let μ1 denote the mean yield for fertilizer A. Use tables to find the critical value and round the answer to one decimal place.

Answer 1

x1    =	460.60	x2      =	400.00
s1    =	31.56	s2      =	22.47
n1    =	10	n2     =	7

Pooled Variance Sp2=((n1-1)s21+(n2-1)*s22)/(n1+n2-2)=

799.7600

point estimate of difference=x1-x2=			60.600
for 90 % CI & 15 df value of t=			1.753
margin of error E=t*std error =			24.4308
lower bound=mean difference-E=			36.17
Upper bound=mean differnce +E=			85.03
from above 90% confidence interval for population mean =(36.2 , 85.0)