In how many ways can a student score 80%? 3 45 56 54 The area under the standard
ID: 3200322 • Letter: I
Question
In how many ways can a student score 80%? 3 45 56 54 The area under the standard normal curve between z = 1 -40 and z = 2.00 is: 0.9772 0.0808 0.8964 0.1036 The area under the normal curve with parameters mu = 3.95 and sigma = 0.30 that between 3.65 and 4.25 is: 0.1587 0.8413 0.6826 0.6000 Studies show that 60% (p =, 60) of U.S. families use physical aggression to conflict. Suppose that 8 families are selected at random. Find the number of families that use physical aggression to resolve conflict is inclusive. 0.375 0.875 0.577 0.575Explanation / Answer
Answer:
15).
Answer: B). 45.
Missing 1 question can happen in 10 ways because there are 10 questions could miss.
If students are randomly guessing, the number of ways to get 90% is 10
Miss a pair of questions--that can happen in 45 ways because there are 10P2 = 45 distinct pairs of questions;
The number of ways to get 80% is 45.
16).
P( -1.40<z<2.00) = P( z <2.00)- P( z <-1.40)
= 0.9772- 0.0808 = 0.8964
Answer: C). 0.8964
17).
Z value for 3.65, z = (3.65-3.95)/0.30 = -1
Z value for 4.25, z = (4.25-3.95)/0.30 = 1
P( 3.65<x<4.25) = P( -1<z<1) =P( z <1) – P( z < -1)
=0.8413 -0.1587
=0.6826
Answer: C). 0.6826
18).
n=8, p=0.6 Binomial distribution used.
P(X=x) = (nCx) px (1-p)n-x
Binomial Probabilities Table
X
P(X)
5
0.2787
6
0.2090
7
0.0896
P= 0.2787+0.2090+0.0896 =0.5773
Answer: C). 0.577
Binomial Probabilities Table
X
P(X)
5
0.2787
6
0.2090
7
0.0896