22. a 95% confidence interval for p is given as (0.49, 0.71) how large was the sample used to construct this interval?

24. It costs you $12 to draw a sample of size n=1 and measure the attribute of interest. you have a budget of $2000.

a) do you have sufficient funds to estimate the population mean for the attribute of interest with a 95% confidence interval 5 units in width? Assume o= 15

Select the correct choice below:

a) Yes, because the required sample size is ___

b) No, because the required sample size is ___

25.in a sample of n=13 lichen specimens, the researchers found the mean and standard deviation of the amount of the radioactive element, cesium -137, that was present to be 0.009 and 0.006 micro curie per milliliter, respectively. Suppose the researchers want to increase the sample size in order to estimate the mean u to within 0.001 micro curie per milliliter of its true value, using a 95% confidence interval. complete parts a-c.

a) what is the confidence level desired by the researchers?

1. in a sample of 70 stores of a certain company, 62 violated a scanner accuracy standard. it has been demonstrated that the conditions for a valid large sample confidence interval for the true proportion of the stores that violate the standard were not met. determine the number of stores that must be sampled in order to estimate the true proportion to within 0.05 with 90% confidence using the large-sample method.

The number of stores that must be sampled is: