The SAT scores for students are normally distributed with a mean of 1000 and a standard deviation of 200. What is the probability that a sample of 73 students will have an average score between 970 and 1010? Round your answer to 3 decimal places.
Solution :
Given that,
mean = = 1000
standard deviation = = 200
= / n = 200 / 73 = 23.4082
= P[(970 - 1000) / 23.4082 < ( - ) / < (1010 - 1000) / 23.4082)]
= P(-1.28 < Z < 0.43)
= P(Z < 0.43) - P(Z < -1.28)
= 0.6664 - 0.1003
= 0.566
Probability = 0.566
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