Variant 2

Date: 2015-10-07; view: 385.

We select a sample with volume n=64 from a normal universal set. The standard deviation is known: σ=40. We find sampling average: =136,5. We need to verify the null hypothesis =130 using competing hypothesis and confidence level 0.01.

We weighted 10 samples of a chemical substance on two scales. We got the following results:

Using confidence level 0.01 verify, if the measurements results differ significantly (we suppose them to be distributed normally)

We approve a production lot if a probability of an item to be damaged is not bigger then 0.03. We selected randomly 250 items and found 28 defected ones. Is it possible to approve a lot (use confidence level 0.05).

Using four independent samples with volumes 15,20,20,14 items correspondingly selected from normal universal sets we found corrected sampling variances: 0.53, 0.78, 0.96, 0.62. Using a confidence level 0.05 verify a null hypothesis on homogeneity of variance

X is normally distributed. Sample volume n=36, sampling average =10.1, the corrected standard deviation s=0.3. Estimate the unknown mean using confident intervals. Reliability g=0.95.