High School

We appreciate your visit to Scores on the Wechsler Adult Intelligence Scale for the 20 to 34 age group are approximately normally distributed 1 What proportion of people aged 20. This page offers clear insights and highlights the essential aspects of the topic. Our goal is to provide a helpful and engaging learning experience. Explore the content and find the answers you need!

Scores on the Wechsler Adult Intelligence Scale for the 20 to 34 age group are approximately normally distributed.

1. What proportion of people aged 20 to 34 have IQ scores above 97.8? (Give your answer as a decimal.)

2. What IQ score falls in the lowest 25% of the distribution?

3. How high an IQ score is needed to be in the highest 5% of the distribution?

Answer :

The proportion of people with IQ scores above 97.8 is 0.5714 or 57.14%.

The IQ score that falls in the lowest 25% of the distribution is 89.88.

The IQ score needed to be in the highest 5% of the distribution is 124.68.

In order to find the proportion of people aged 20 to 34 who have IQ scores above 97.8,

we have to use a standard normal distribution table.

Converting the IQ score to a z-score, we get,

⇒ z = (97.8 - mean) / standard deviation

Assume a mean IQ score of 100 and a standard deviation of 15 (as is typical for IQ tests), we get,

⇒ z = (97.8 - 100) / 15

= -0.18

Using a standard normal distribution table,

We can find that the proportion of people with IQ scores above 97.8 is 0.5714 or 57.14%.

To find the IQ score that falls in the lowest 25% of the distribution,

we have to find the z-score that corresponds to the 25th percentile. Using a standard normal distribution table,

we get a z-score of -0.675.

We can then convert this back to an IQ score,

⇒ IQ score = mean + (z-score x standard deviation)

⇒ IQ score = 100 + (-0.675 x 15)

= 89.875

So the IQ score that falls in the lowest 25% of the distribution is 89.88.

Now to find the IQ score needed to be in the highest 5% of the distribution,

we have to find the z-score that corresponds to the 95th percentile. Using a standard normal distribution table,

We get a z-score of 1.645. We can then convert this back to an IQ score,

⇒ IQ score = mean + (z-score x standard deviation)

⇒ IQ score = 100 + (1.645 x 15)

= 124.68

So the IQ score needed to be in the highest 5% of the distribution is 124.68.

To learn more about statistics visit:

https://brainly.com/question/30765535

#SPJ4

Thanks for taking the time to read Scores on the Wechsler Adult Intelligence Scale for the 20 to 34 age group are approximately normally distributed 1 What proportion of people aged 20. We hope the insights shared have been valuable and enhanced your understanding of the topic. Don�t hesitate to browse our website for more informative and engaging content!

Rewritten by : Barada