sample mean

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 interv..

The average price for different configurations of laptops in a shop is $1,300. Assume the standard deviation is $300. If a random sample of 9 laptops is selected, then find the probability that the mean of the sample will be less than $1,000. => 0.13% or 49.87% or 99.8..

If two samples have means of 30 and 28 and variances of 12 and 14, with 20 and 25 as the sizes, find the z score for difference of two population means. => 2.154 or 2.075 or 2.320 or 1.857..

The mean weight of girls in grade 12 of school X is 125 pounds, and the standard deviation is 20 pounds. If a sample of 25 girls is selected, then what is the probability that the mean of the sample will be greater than 128 pounds? Assume the variable is norm..

As the sample size n increases without limit, the shape of the distribution of the sample means taken with replacement from a population with mean μ and standard deviation σ will approach a normal distribution. This distribution will have mean..

90% confidence interval of a population mean(μ) worked out on a sample size of 50 is, 50 < μ < 56. What is the likely 90% confidence interval of the mean of the same population worked out on a sample size of 100? => 25 < μ < 28 or 51 <..

The normal monthly precipitation (in inches) for a sample of 32 cities is shown. Estimate the mean precipitation(μ) per city with 99% confidence. => 1.92 < μ < 3.12 or 1.71 < μ < 3.22 or 2.24 < μ < 3.06 or 2.16 < μ < 3.24..

In 2002 Football World Cup finals tournament a total of 64 matches were played and an average of 2.52 goals were scored per match. Assume the standard deviation to be 1.5. If a random sample of 10 games is selected, then find the probability that the mean of the sample..

A management firm wants to estimate the mean cost of repairing the apartments that are vacated by tenants. A sample of 18 vacated apartments resulted in a mean repair cost of $109 with a standard deviation of $12. Find the 90% confidence interval to estimate the m..

A random sample of 86 days taken at a large hospital shows that an average of 32 patients were treated per day. The 95% confidence interval of the mean number of patients treated each day at the hospital is between 30 and 34. Find the 95% confidence interval of the mean..