Determine the T-Value in each of the cases: (a) Find the t-value such that the a

Question

Determine the T-Value in each of the cases:

(a) Find the t-value such that the area in the right tail is .20 with 11 degrees of freedom.

(b) Find the t-value such that the area in the right tail is .10 with 12 degrees of freedom.

(c) Find the t-value such that the area left of the t-value is .05 with 17 degrees of freedom.

(d) Find the critical t-value that corresponds to 50% confidence. Assume 24 degrees of freedom.

A survey of 2298 adults in a certain large country aged 18 and older conducted by a reputable polling organization found that 414 have donated blood in the past two years. Complete parts (a) through (c) below

(a) Obtain a point estimate for the population proportion of adults in the country aged 18 and older who have donated blood in the past two years.

p-hat = ____ (round to three decimal places as needed.

(b) Verify that the requirements for constructing a confidence interval about p are satisfied.

The sample: can be assumed to be, is stated to not be, is stated to be, cannot be assumed to be, a simple random sample, the value of : p-hat, n, p-hat(1-phat), nphat (1-phat), nphat which is greater than or equal to, less than  10, and the (population size, sample proportion, population proportion, sample size ) / ( is stated to not be, cannot be assumed to be, can be assumed to be, is stated to be) less than or equal to 5% of the (population proportion, sample size, sample proportion, population size.)

(c) Construct and interpret a 90% confidence interval for the population proportion of adults in the country who have donated blood in the past two years. Select the correct choice below and fill in any answer boxes within your choice.

(Type integers or decimals rounded to three decimal places as needed. Use ascending order.)

1- We are ___% confident the proportion of adults in the country aged 18 and older who have donated blood in the past two years is between ____ and ___.

2- There is a ___% chance that the proportion of adults in the country aged 18 and older who have donated blood in the past two years is between ___ and ___.

Explanation / Answer

(1)

(a) Area = 0.2, df = 11, t = 0.8755

(b) Area = 0.1, df = 12, t = 1.3562

(c) Area = 0.05, Df = 17, t = -1.7396

(d) Df = 24, Confidence = 50%, Critical t = 0.6848

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