Math

QuestionFor a distribution N(5.43,0.54)N(5.43,0.54), find the proportion of observations less than 5.05 and 5.79, rounded to four decimal places.

Studdy Solution

STEP 1

Assumptions1. The distribution is Normal with a mean of5.43 and a standard deviation of0.54. . We are looking for the proportion of observations less than5.05 and5.79.

STEP 2

First, we need to standardize the values5.05 and5.79 using the formula for the z-score. The z-score is a measure of how many standard deviations an element is from the mean.
Z=XμσZ = \frac{X - \mu}{\sigma}where- X is the value from the dataset, - μ\mu is the mean of the dataset, - σ\sigma is the standard deviation of the dataset.

STEP 3

Now, plug in the given values for the first value (5.05), mean and standard deviation to calculate the z-score.
Z5.05=5.055.430.54Z_{5.05} = \frac{5.05 -5.43}{0.54}

STEP 4

Calculate the z-score for the value.05.
Z.05=.05.430.54=0.7037Z_{.05} = \frac{.05 -.43}{0.54} = -0.7037

STEP 5

Now, plug in the given values for the second value (5.79), mean and standard deviation to calculate the z-score.
Z5.79=5.795.430.54Z_{5.79} = \frac{5.79 -5.43}{0.54}

STEP 6

Calculate the z-score for the value5.79.
Z5.79=5.795.430.54=0.666Z_{5.79} = \frac{5.79 -5.43}{0.54} =0.666

STEP 7

The z-scores represent the distance between the mean and the given values in terms of standard deviations. Now, we need to find the proportion of observations that are less than these z-scores. We can do this by looking up the z-scores in a standard normal distribution table or using a calculator with a normal distribution function.

STEP 8

Look up the z-score for5.05 in a standard normal distribution table or use a calculator with a normal distribution function.
(Z<0.7037)(Z < -0.7037)

STEP 9

Calculate the proportion of observations less than5.05.
(Z<.7037)=.2408(Z < -.7037) =.2408

STEP 10

Look up the z-score for5.79 in a standard normal distribution table or use a calculator with a normal distribution function.
(Z<0.6667)(Z <0.6667)

STEP 11

Calculate the proportion of observations less than5.79.
(Z<0.6667)=0.7525(Z <0.6667) =0.7525The proportion of observations less than5.05 is0.2408 and the proportion of observations less than5.79 is0.7525.

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