When the probability is 0.77 for the sample mean to be greater than certain value, tis value is solved to be 4.3
The problem will be solved with t-scores as the number of sample is less than 30
number of sample, n = 25
degree of freedom, df
= n - 1
= 25 - 1 = 24
Assuming a confidence level of 95%, probability of 0.77, with a df of 24 the t-score is 2.064
the question is asking for greater than = 1 - 2.064 = -1.064
Using the formula for t scores
t = (X - μ) / σ
Definition of variables
mean, μ = 4.70
standard deviation, σ = 0.40
-1.064 = (X - 4.7)/0.4
-1.064 * 0.4 = X - 4.7
-0.4256 = X - 4.7
-0.4256 + 4.7 = X
X = 4.2744 approximately 4.3
Learn more about t-scores at:
https://brainly.com/question/6501190
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