Jenny is taking AP Statistics and AP U.S. History. Jenny scored a 95 on an AP Statistics test where the mean score was 84 with a standard deviation of 4.5. She then scored a 90 on an AP U.S. History test with a mean score of 75 and a standard deviation of 8.2. On which test did Jenny perform better relative to others who have taken the test? Justify your answer.

Respuesta :

Answer:

Jenny performed better in statistic test as compared to history exam.

Step-by-step explanation:

We are given the following information in the question:

AP Statistics

Mean, μ = 84

Standard Deviation, σ = 4.5

AP U.S. History

Mean, μ = 75

Standard Deviation, σ = 8.2

We are given that the distribution of  scores are a bell shaped distribution that is a normal distribution.

Formula:

[tex]z_{score} = \displaystyle\frac{x-\mu}{\sigma}[/tex]

P(AP statistic score of 95)

P(x < 95)

[tex]P( x < 95) = P( z < \displaystyle\frac{95 - 84}{4.5}) = P(z < 2.445)[/tex]

Calculation the value from standard normal z table, we have,  

[tex]P(x < 95) =0.993 = 99.3\%[/tex]

P(AP U.S. History of 90)

P(x < 90)

[tex]P( x < 90) = P( z < \displaystyle\frac{90 - 75}{8.2}) = P(z < 1.829)[/tex]

Calculation the value from standard normal z table, we have,  

[tex]P(x < 95) =0.966 = 96.6\%[/tex]

Jenny did better on AP statistics, because she scored better than 99.3% of the students on statistics exam that is her percentile is 99.3% as compared to 96.6% of the students on the history exam where her percentile is 96.6%.

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