4. Scores on a standard IQ Test for young adults aged 20 to 34 are normally dist

Question

4. Scores on a standard IQ Test for young adults aged 20 to 34 are normally distributed with tion 25. You must write the correct notation for probability. You must drow correct, well-ordered functional notations as given in the graphing must drow a well labeled, well-shaded normal curve. If you are using the graphing calculator to then you must write the Warning: Writing only the numerical answer will not get probabilities, calculator. get full credits. a What percent of young aduls score below 75 on this 1Q Test? b. What is the probability that a young adult will score above 180 on this IQ Test? c What is the probability that a young adult will score between 85 and 160 on this IQ Test? d Hally only wants to date men in the top 15% on this intelligence scale. How high must a man score for Hally to date him?

Explanation / Answer

Solution:

X follows normal distribution wth mean 110 sd=25

P(X<75)

z=x-mean/sd

z=75-110/25

=-1.4

P(Z<-1.4)

that is=1-P(Z<1.4)

=1-0.9192

=0.0808

P(Z<75)=0.0808

Solutionb:

P(X>180)

Z=180-110/25=2.8

P(Z>2.8)

=1-P(Z<2.8)

=1-0.9974(from normal distribution table)

=0.0026

P(X>180)=0.0026

ANSWER:0.0026

Solutionc;

P(85<X<160)

P(85-110/25<Z<160-110/25)

=P(-1<Z<2)

=P(Z<2)-P(Z<-1)

=0.9772-(1-P(Z<1)

=0.9772-0.1587

=0.8185

P(85<X<160)=0.8185

ANSWER:0.8185

Solutiond:

z score for top15% is

z=-1.036

z=x-mean/sd

x-110/25=-1.036

x=-1.036*25+110

x=84.1

he must score 84.1

Related Questions

Navigate

• Browse (All)
• Browse 4
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.