60 C1813 Pages: 3

OR
18 a) Two independent random samples of sizes 8 and 10 are taken from a normal (3) population. Find
an upper bound to the ratio of the variances of the 2 samples such that the probability of the
ratio exceeding the bound is 0.05.

b) A random sample of size 11 from a normal population is found to have variance 12.3.
(3) Find a 95% confidence interval for the population variance.
Module VI
19 2) Define the following: (3)
i) Null hypothesis ii) Alternate hypothesis 1) Level of significance

b) The heights of students studying in college classes is believed to be distributed with (3) SD 1.5. A
sample of 400 students have their mean height 4.75 ft. Does this contradict the hypothesis that
the mean height of students is 4.48 ft. (significance level is 1%)?

OR

20 a) The records of a certain hospital showed the birth of 723 males and 617 females in a (3) certain
week. Do these confirm to hypothesis that the sexes are born in equal proportion.

b) Random samples of sizes 500 and 400 are found to have means 11.5 and 10.9 (3) respectively. Can
the samples be regarded as random samples drawn from the same population whose SD is 5?

بد بد ید ‎मैप‏

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