There is not enough evidence to support the administrator’s claim and the true mean is not significantly greater than 280.
<h3>What is a statistical hypothesis?</h3>
A hypothesis to test the given parameters requires that we determine if the mean score of the eighth graders is more than 283, thus:
The null hypothesis:

The alternative hypothesis:

From the population deviation, the Z test for the true mean can be computed as:


Z = 0.756
Note that, since we are carrying out a right-tailed test, the p-value for the test statistics is expressed as follows:
P(z > 0.756)
P = 0.225
Since the P-value is greater than the significance level at α = 0.14, we can conclude that there is not enough evidence to support the administrator’s claim and the true mean is not significantly greater than 280.
Learn more about hypothesis testing here:
brainly.com/question/16251072
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Answer:
x= 90-60
x=30
Step-by-step explanation:
Answer:
A function is a type of <em><u>vertical line </u></em><em><u>test.</u></em>
Answer:
0.24315
Step-by-step explanation:
Using the z score formula to solve this question
z = (x - μ) / σ,
Such that:
x = raw score
μ = population mean
σ = population standard deviation.
From the question:
x = 3000
μ = 3550
σ = 870
z = (3000 - 3550) / 870
z = -550/870
z = -0.6962
Using the z score table as well as probability calculator(as requested in the question to find the z score)
The probability of having less than 3000 is obtained as:
P(x<3000) = 0.24315