2.Find the z-score boundary that separates a normal distribution as described in
ID: 3208735 • Letter: 2
Question
2.Find the z-score boundary that separates a normal distribution as described in each of the following: The lowest 20% of scores the top 40% of scores The bottom 75% of scores The top 99% of scores
3.For a normal distribution with a mean of=80 and a standard deviation of sx=20. Find the proportion of the population corresponding to each of the following scores. Scores greater than 85 Score less than 100 Scores between 70 and 90
4. IQ test scores are standardized to produce a normal distribution with a mean of =100 and a standard deviation of sx=15. Find the proportion of the distribution in each of the following IQ categories. Genius or near genius: IQ greater than 140 Very superior intelligence: IQ between 120 and 140 Average or normal intelligence: IQ between 90 and 109
5.The distribution of scores on the SAT is approximately normal with a mean of =500 and a standard deviation of sx=100. For the distribution of students who have taken the SAT, What proportion have SAT scores greater than 700? What proportion have SAT scores greater than 550? What is the minimum SAT score needed to be in the highest 10% of the population? If the state college only accepts students from the top 60% of the distribution, what is the minimum SAT score needed to be accepted?
1.Four airplanes from different airlines have crashed in the past two week. This terrifies Megan, who must travel on a plane. Her travel agent claims that the probability of a plane crash is minuscule. Who is correct and why?
Explanation / Answer
2) Lowest 20% = P(Z) = 0.2
So, Z = -0.84
Top 40% means P(Z) = 1-0.4 = 0.6
So, Z = 0.253
Bottom 75% means P(Z) = 0.75
So, Z = 0.675
Top 99% means bottom 1% = P(Z) = 0.01
So, Z = -3.1
(Please post the remaining questions separately)
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