Variant 3

Date: 2015-10-07; view: 403.

We select a sample with volume n=64 from a normal universal set. The standard deviation is known: σ=50 We find sampling average =146,5. We need to verify the null hypothesis =150 using competing hypothesis .and confidence level 0.01

We measured 6 items using two devices and got the following results:

Using the confidence level 0.05 verify, if the measurements results differ significantly (we suppose the size of item is distributed normally)

We approve a production lot if a probability of an item to be damaged is not bigger then 0.02. We selected randomly 480 items and found 12 defected ones. Is it possible to approve a lot? (use confidence level 0.05).

Using four independent samples with volumes 28,34,30,31 items correspondingly selected from normal universal sets we found corrected sampling variances: 0.03, 0.17, 0.11, 0.02. Using a confidence level 0.05 verify a null hypothesis on homogeneity of variance

X is normally distributed. Sample volume n=26, sampling average =25, the corrected standard deviation s=1.8. Estimate the unknown mean using confident intervals. Reliability g=0.95.