Q.No.1. (a) the general social survey polled a sample of 200 people aged 18-30 in the year 2000,asking them how many hours per week they spent on the internet. The sample average was 7.67 with standard deviation of 7.71. a second sample of 541 people aged 18-30 was taken in year 2006. For this sample the average 8.74 with standard deviation of 10.93.assume these are simple random sample from population of People aged 18-30.can u conclude that mean number of hours per week spend on internet increased between 2000 and 2006.use 1% level of significance. (b). consider the following confidence interval drawn from sample size of 100 specimens with standard deviation 2.  (Interval 11.5- 19.5) (i)What is value of sample mean? (ii)What is confidence level associated with the given interval

Definition Definition Measure of central tendency that is the average of a given data set. The mean value is evaluated as the quotient of the sum of all observations by the sample size. The mean, in contrast to a median, is affected by extreme values. Very large or very small values can distract the mean from the center of the data. Arithmetic mean: The most common type of mean is the arithmetic mean. It is evaluated using the formula: μ = 1 N ∑ i = 1 N x i Other types of means are the geometric mean, logarithmic mean, and harmonic mean. Geometric mean: The nth root of the product of n observations from a data set is defined as the geometric mean of the set: G = x 1 x 2 ... x n n Logarithmic mean: The difference of the natural logarithms of the two numbers, divided by the difference between the numbers is the logarithmic mean of the two numbers. The logarithmic mean is used particularly in heat transfer and mass transfer. ln x 2 − ln x 1 x 2 − x 1 Harmonic mean: The inverse of the arithmetic mean of the inverses of all the numbers in a data set is the harmonic mean of the data. 1 1 x 1 + 1 x 2 + ...