statistics

1)A random sample of 100 selected from a population with a standard deviation of 10 yielded a mean = 225. The mean and the standard deviation of the distribution of the sample means are ___&___

2)Suppose a random sample of 400 is selected from a population with a standard deviation of 5. If the sample mean is 25, the 98% confidence interval to estimate the population mean is between___

3)The following random sample was selected from a normal distribution: 4.5, 6.4, 2.3, 1.8, 5.3, then the 95% confidence interval to estimate the population mean is between____

4)A department store finds that in a random sample of 200 customers, 60% of the sampled customers had browsed its website prior to visiting the store. Based on this data, a 90% confidence interval for the population proportion of customers that browse the store’s website prior to visiting the store will be between__

5)Given the mean and the variance from a sample of size 15 are, 28 and 45, respectively, then the 95% confidence interval for the population variance σ² is___