Variant 4

Date: 2015-10-07; view: 389.

The size of items which were made on a factory is =35millimeters. We tested 20 items that were selected randomly (data are presented in a table). Using confidence level 0.05, verify if there is a common deviation in a selected item set.

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 0.02. We selected randomly 600 items and found 40 defected ones. Is it possible to approve a lot (use confidence level 0.05)?

Using four independent samples with volumes 14,30,20,16 items correspondingly selected from normal universal sets we found corrected sampling variances: 0.52, 0.84, 0.76, 0.69. Using a confidence level 0.05 verify a null hypothesis on homogeneity of variance

X is normally distributed. Sample volume n=50, sampling average =22, the corrected standard deviation s=3.2. Estimate the unknown mean using confident intervals. Reliability g=0.95.