Ask question

Ask question

All categories

3 years ago

8

In a study of the stability of IQ scores, a large group of individuals is tested once at age 18 and again at age 35. The followi

ng results are obtained.
Age 18: average score = 100, SD = 15
Age 35: average score = 100, SD = 15, r = 0.80
(a) Estimate the average score at age 35 for all the individuals who scored 115 at age 18.
(b) Predict the score at age 35 for an individual who scored 115 at age 18.

1 answer:

Naddika [18.5K]3 years ago

5 0

Answer:

112

Step-by-step explanation:

Given that in a study of the stability of IQ scores, a large group of individuals is tested once at age 18 and again at age 35.

Age 18: average score = 100, SD = 15

Age 35: average score = 100, SD = 15, r = 0.80

Let us obtain regression equation of y on x.

Let y be the scores at age 35 and x at age 18

Slope = $r(s_y/s_x) = 0.8(\frac{15}{15} )=0.80$

The line passes through (100,100) being average of x and y

Hence regression line would be

$y-100=0.8(x-100)\\y = 0.8x+20$

a) Here given that x =115

Hence $y=0.80(115)+20\\=112$

the average score at age 35 for all the individuals who scored 115 at age 18, would be 112.

b) Prediction also would be the same 112.

You might be interested in

Divide £945 in the ratio 2:5

dybincka [34]

The answer is 675. 2270. 657

5 0

3 years ago

Solve this equation using the radical equation method

Yuki888 [10]

The domain:
$3x+6\geq0\ \ |-6\\3x\geq-6\ \ \ |:3\\x\geq-2\\\\D:x\in\left< -2;\ \infty\right)$

$2x=\sqrt{3x+6}-1\ \ \ |+1\\\\2x+1=\sqrt{3x+6}\ \ \ \ |^2\\\\(2x+1)^2=\left(\sqrt{3x+6}\right)^2\ \ \ |use:\ (a+b)^2=a^2+2ab+b^2\\\\(2x)^2+2\cdot2x\cdot1+1^2=3x+6\\\\4x^2+4x+1=3x+6\ \ \ \ |-3x-6\\\\4x^2+x-5=0\\\\4x^2-4x+5x-5=0\\\\4x(x-1)+5(x-1)=0\\\\(x-1)(4x+5)=0\iff x-1=0\ \vee\ 4x+5=0\\\\x=1\ \vee\ 4x=-5\\\\x=1\in D\ \vee\ x=-1.25\in D$

$Answer:\ \boxed{x=-1.25\ \vee\ x=-1}$

6 0

3 years ago

Evaluate the integral. (remember to use absolute values where appropriate. Use c for the constant of integration.) 5 cot5(θ) sin

ozzi

$I=5\int \frac{cos^{4}\theta }{sin\theta }\times cos\theta d\theta \\\\I=5\int \left ( 1-sin^{2}\theta \right )^{2}\times \frac{cos\theta }{sin\theta }d\theta \\put\ \sin\theta =t\\\\dt=cos\theta d\theta \\\\I=5\int\frac{t^{4}+1-2t^{2}}{t}dt\ \ \ \ \ \ \ \ \ \ \because (a-b)^2=a^2+b^2-2ab\\\\I=5\left ( \int t^{3}dt + \int \frac{1}{t} -2\int t \right )dt$

by using the integration formula

we get,

$\\I=5\left ( \frac{t^{4}}{4} +logt -t^{2}\right )\\\\I=\frac{5}{4}t^{4}+5\log t-5t^{2}+c$

now put the value of t=\sin\theta in the above equation

we get,

$\int 5\cot^5\theta \sin^4\theta d\theta=\frac{5}{4}sin^{4}\theta+5\log \sin\theta - 5sin^{2} \theta+c$

hence proved

7 0

3 years ago

Function Question :)<br><br> Please explain reasoning.

WITCHER [35]

Answer:

pota pota pota thats the song

6 0

2 years ago

Which fraction is bigger 7/8 or 14/15 using lcm

Sever21 [200]

Between 7/8 and 14/15 the bigger value is the 7/8. When comparing to fractions you need look on the denominator of the fractions the smaller the denominator the larger the fraction. Thank you for posting your question here. Hope it helps.

4 0

3 years ago