the results of a certain medical test are normally distributed with a mean of 124 and a standard deviation…

the results of a certain medical test are normally distributed with a mean of 124 and a standard deviation of 13. convert the given results into z - scores, and then use the accompanying table of z - scores and percentiles to find the percentage of people with readings between 112 and 136. click the icon to view the table of z - scores and percentiles. the percentage of people with readings between 112 and 136 is %. (round to two decimal places as needed.)
Answer
Explanation:
Step1: Calculate z - score for 112
The z - score formula is $z=\frac{x-\mu}{\sigma}$, where $\mu = 124$, $\sigma=13$ and $x = 112$. $z_1=\frac{112 - 124}{13}=\frac{- 12}{13}\approx - 0.92$
Step2: Calculate z - score for 136
Using the same formula with $x = 136$, $\mu = 124$ and $\sigma = 13$. $z_2=\frac{136-124}{13}=\frac{12}{13}\approx0.92$
Step3: Find the percentiles
From the z - score table, the percentile corresponding to $z=-0.92$ is approximately $0.1788$ and the percentile corresponding to $z = 0.92$ is approximately $0.8212$.
Step4: Calculate the percentage between the two values
The percentage of people with readings between 112 and 136 is $P(112<X<136)=0.8212 - 0.1788=0.6424$
Answer:
$64.24$