Answer:
95% Confidence interval: (96.06,103.94)
Step-by-step explanation:
We are given the following in the question:
Population mean, μ = 85
Sample mean, = 100
Sample size, n = 30
Alpha, α = 0.05
Population standard deviation, σ = 11
95% Confidence interval:
Putting the values, we get,
(96.06,103.94) is the 95% confidence interval for the population mean test score.
Answer:
38.11%
Step-by-step explanation:
Given that:
Mean (μ) = 75, standard deviation (σ) = 5
Z score is a measure in statistics to determine the variation of a raw score from the mean. It is given by the equation:
To calculate the percentage of students scored between a 73 and 78 (C grade), we need to find the z score for 73 and then for 78.
For x = 73, the z score is:
For x = 78, the z score is:
From the probability distribution table:
P(73 < x < 78) = P(-0.4 < z < 0.6) = P(z < 0.6) - P(z < -0.4) = 0.7257 - 0.3446 = 0.3811 = 38.11%