A company has been producing steel tubes of mean inner diameter of 2 cm. A sample of 10 tubes gives an inner diameter of 2.01 cm and a standard deviation of 0.063 cm. If $t_9(0.05)=2.262$, then which of the following is NOT correct?

A sample of size 9 from a normal population with sample mean $\bar{X} = 15.8$ and population estimated standard deviation $\sigma = 3.21$, then 99% confidence interval for population mean is : $(Use: t_8(0.01) = 3.335)$

Which of the following are true ?

(A) If the mean of a normal variate is 12 and standard deviation is 4, then the Z-score of data point 20 is 2.

(B) Mean of the numbers obtained on throwing a die having '1' on three faces, '2' on two faces and '5' on one face is 3.

(C) If the variance of a Poisson's distribution is 2, then $P(X=0)=\frac{1}{e^2}$.

(D) For a binomial distribution, mean = 9 and the standard deviation is $\frac{3}{2}$, then the number of trials is 12.

Choose the correct answer from the options given below:

In reference to Inferential Statistics, for 20 degrees of freedom, the least statistical t-value among the given below is:

With reference to sampling, which of the following are correct?

(A) Simple random sampling is probability sampling

(B) Snow-ball sampling is non-probability sampling

(C) Stratified sampling is probability sampling

(D) Cluster sampling is non-probability sampling

Choose the correct answer from the options given below:

If 95% confidence interval for the population mean was reported to be 140 to 150 and $\sigma = 25$, then size of the sample used in this study is:

[Given: $Z_{0.025} = 1.96$]

A random sample of size 16 has 53 as mean. The sum of the squares of the deviations taken from mean is 150. If the population mean is 56 then the value of t-test statistic is: