PLEAS HELP I WILL GIVE 10 POINTS
1 answer:
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Answer:
B. 359
Step-by-step explanation:
Given that:
The margin of error (e) must be within 0.3 unit, The standard deviation (σ) = 2.9 and the the confidence level = 95% = 0.95
α = 1 =0.95 = 0.05
The z score of 0.025 corresponds to the z score of 0.0475 (0.5 - 0.025) which can be gotten from the normal probability table.
Therefore:
The formula for the margin of error is given by:
Therefore the smallest sample size (n) is 359
The probability of the sample is 0.5 or 50%
<u>Explanation:</u>
Given:
Mean, μ = 20
Standard deviation, δ = 1.3
Probability of sample being less than 20.1 = ?
P (x < 20.1) = 20.1 - μ / δ √n
P (x < 20.1) =
= 0.0098
P( x < 20.1) = P(z < 0.0098)
P (z < 0.0098) = 0.5
The value of P is found out using a z score table.
Therefore, probability of the sample is 0.5 or 50%