sample test

A sample of 30 RAM chips was tested for the average access time. The standard deviation was found to be 2 nanosec. Find the 90% confidence interval for the true standard deviation. Assume that the variable is normally distributed. => between 1.7 and 2.6 or between 1.6 and 2.5 or..

A survey reported that 70% of college students aged 18 to 26 own a cell phone. To test this report a professor selected a random sample of 150 college students and found that 100 own a cell phone. Is the sample report differs from population report at α = 0.05? W..

01. A point charge of 1.8 m C is at the centre of a cubical Gaussain surface having each side 50cm. What is the net electric flux through the surfac..

The mean score on a standardized test is 100 with a standard deviation of 8. A random sample of 48 scores was found to have a mean of 98. Find the 95% confidence interval. => The interval is between 97.75 and 102.25 or The interval is between 1.15 and 100 or The interval is betw..

Radio tubes manufactured by a company are expected to have a mean lifetime of 400 hours, with a standard deviation of 30 hours. Random samples of 10 tubes were tested. It was found that 3 tubes had a lifetime of 398 hours, 5 of them had a lifetime of 410 hours and 2 had a lifeti..

A survey reported that 64% of the children of 12 to 15 years of age play online games. In a sample of 200 of this age group, 150 responded positively. Test the survey report at α = 0.01. => z = 3.24, there is enough evidence to reject the survey report or z = 1.62, there i..

The population survey in 2001 stated that 37% of urban workers held multiple jobs in order to earn extra money. From a random sample of 200 urban workers taken, it was found that 70 of them held multiple jobs. Find the p -value for the test. Does the sample proportion ..

What shall be the most important objective of selecting sample from a population? => Sample selection shall be cost saving. or Each subject in the population shall have an equally likely chance of being selected. or Maximum number of samples shall represent the populat..

The variance of the number of pages of a sample of 20 women's fitness magazines is 62 and the variance of the number of pages of a sample of 15 sports magazines is 23. At 90% confidence level, find the F-test value and check whether variances differ significantly. => 2..

Find the F-test value and the critical value at 95% confidence for testing the population variances. The data relating to samples are shown. Sample size Sample variance 30 12 25 8 => 1.2, 2.15 or 2.15, 1.2 or 1.94, 1.5 or 1.5, 1.94..