Let us suppose that two independent random samples of sizes $n_1$ and $n_2$ has been drawn from the same normal population then degree of freedom of statistic t-distribution is:

In a survey question for a sample of 250 individuals, 120 persons gave response 'yes', 80 persons gave response 'no' and 50 gave 'no response'. The point estimate of the proportion in the population who responded 'yes' is:

The point estimate of the population standard deviation for the random sample 5, 8, 10, 7, 10, 14 is:

Consider the following hypothesis test:

$H_0: \mu \leq 12$

$H_a: \mu > 12$

A sample of 25 provided a sample mean $\bar{x} = 14$ and a sample standard deviation $s = 4.32$. If $t_{0.05} = 1.711$, then which of the following is correct?

(A) The test statistic is defined as $t = \frac{\bar{x} - \mu}{\frac{s}{\sqrt{n}}}$.

(B) The value of the test statistic is 1.31.

(C) At $\alpha = 0.05$, the null hypothesis is rejected.

(D) If the value of the t-statistic is less than $t_\alpha$, then null hypothesis is accepted.

Choose the correct answer from the options given below:

If $95 \%$ confidence interval for the population mean was reported to be $160$ to $170$ and $\sigma=25$, then size of the sample used in this study is: (Given $\mathrm{Z}_{0.025}=1.96$ )

If $x_1, x_2, x_3, ..., x_n$ are n observations in a sample then which of following is/are TRUE?

(A) The mean $\bar{x}$ has n degree of freedom

(B) The mean $\bar{x}$ has (n-1) degree of freedom

(C) The standard deviation of the sample has (n-1) degree of freedom

(D) The standard deviation of the sample has n degree of freedom

Choose the correct answer from the options given below:

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 : $(Use: t_8(0.01) = 3.335)$