Question

A random sample of 18 venture capital investments in the fiber optics business sector yielded a sample mean of $6.33 million. 

1. What is the critical z-score value, zc, for an 80% confidence interval? Provide a screenshot of your answer.

2. Use your answer in (1.) to determine the margin of error for an 80% confidence interval for the mean amount of all venture-capital investments in the fiber optics business sector. Assume that the population is normally distributed and the population standard deviation is $2.04 million. Show complete solutions. Round off your answer to 2 decimal places. 

3. Use your answer in (2.) to construct an 80% confidence interval. 

4. Interpret your answer in (3.)

Answer 1

solution - Given data Sample site na 18 Sample mean = 633 Given 2= 1-0.80 de 0. Coitical value of Zc= 1.28 [from coitical vale calculator from a १. z 2] Standard deviation 6= 2.04 of error E= Z c. 6 s ro 틈 E = 128 X 2.04 d18 E = 1,98 x 0.4808 = 0.6154 0.6215 a a margin of Error E= 0.62 3. sol. confidence interval äte C.I – 6 33 +0.69 CI 6,33 +0.62) = (6.33-0.62, (5.) 6.95) CI 4. Interpretation: are 80% confidence interval is ljes between we 5.71 < i <6.95