Solve the system of equations
1 answer:
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Answer:
Probability = 0.00621
Step-by-step explanation:
We are given;
Population mean; μ = 400
Population standard deviation; σ = 20
Raw score; x¯ = 450
the probability that the actual costs will exceed the budgeted amount will be the p-value.
Thus, let's first find the z-score after which we will find the p-value.
z = (x¯ - μ)/σ
z = (450 - 400)/20
z = 50/20
z = 2.5
From online p-value from z-score calculator attached, using z = 2.5; one tailed hypothesis; significance level of 0.05, we have;
P-value = 0.00621
Answer:
We can claim with 95% confidence that the proportion of executives that prefer trucks is between 19.2% and 32.8%.
Step-by-step explanation:
We have a sample of executives, of size n=160, and the proportion that prefer trucks is 26%.
We have to calculate a 95% confidence interval for the proportion.
The sample proportion is p=0.26.
The standard error of the proportion is:
The critical z-value for a 95% confidence interval is z=1.96.
The margin of error (MOE) can be calculated as:
Then, the lower and upper bounds of the confidence interval are:
The 95% confidence interval for the population proportion is (0.192, 0.328).
We can claim with 95% confidence that the proportion of executives that prefer trucks is between 19.2% and 32.8%.