class intervals

The daily water usage (in gallons per person per day) of 10 families of a colony has a variance of 286. Find the 90% confidence interval for the variance and standard deviation. Assume that the variable is normally distributed. => 152 < σ 2 < 774 ; 12 < σ < 28 or 1..

A recent study of 160 people of a locality in a city found that 39 people were obese. Find the 95% confidence interval of the population proportion of individuals living in that city who are obese. => 17.7% < p < 31.1% or 17% < p < 31% or 21% < p < 27.8% or 24.4% < p ..

A survey of 90 recent fatal traffic accidents showed that 52 were alcohol-related. Find the 90% confidence interval of the true proportion of alcohol-related accidents. => 49.4% < p < 66.6% or 50% < p < 66% or 0.49% < p < 0.66% or 52.8% < p < 63.2%..

A television channel conducted a survey of 90 adults and found that 54 regularly watch television at home. Find a 90% confidence interval of the true proportion of adults who watch television regularly. => 59.6% < p < 60.4% or 50% < p < 60% or 54.8% < p < 65.2% or 51.5% ..

The table shows the number of students admitted in a school from 1995 to 2000. If the number of students admitted is taken on the vertical axis, what should be the appropriate interval to draw the graph? Year 1995 1996 1997 1998 1999 2000 Number of Students 78 76 66 72 85 98 => 5 or 35 or..

95% confidence interval of a population mean with a sample size of 18 was found out as 6.17 < μ < 6.99. Another study calculated the 95% confidence interval as 5.71 < μ < 7.46. Which among the following can be the possible sample size of the second study? => 20..

The total expenses (in billion dollars) for recreation spent for a period of 10 consecutive years by a country are shown here. Find the 98% confidence interval for the standard deviation. Assume that the variable is nomally distributed. 13 14.1 15.2 16.2 16.9 17.3 18.3 19.9 20.7 16 => bet..

A random sample of the assets (in millions of dollars) of 10 families of a colony is shown. Find the 80% confidence interval for the variance of the assets. Assume that the variable is normally distributed. 0.5 1 0.4 1.3 0.8 1.2 0.9 2 0.7 1.5 => between 0.158 and 0.529 or between 0.147 an..

Samples of concrete blocks were tested in a lab to determine the crushing strength of the concrete. The crushing strength of block E was missing from the final records. The sample mean of the crushing strength was recorded as 4.45 tonnes/cm 2 . Find the crushing strength of block E and 90% confiden..

A retail garment shop receives a shipment of trousers, with a standard length of 49.0 in. and a standard deviation of 1.0 inch. A random sample of 32 trousers had a mean length of 48.8 in. Find the 95% confidence interval. => The interval between 48.65 and 49.35 or The inte..