Example # 2: Find
Za
for the confidence level 90%.
2
Example # 3:
Find 2, for the confidence level 99%.

(a) 1.645

(b) 2.5758

Step-by-step explanation:

The complete question is: Find Z(/2) for the confidence level 90% and for the confidence level 99%.

Firstly, as we know that represent the level of significance, i.e;

Level of significance = 1 - confidence level

(a) We are given the confidence level of 90%, so;

     Level of significance = 1 - 90%

                                         = 1 - 0.90 = 0.10 or 10%

Now, = =

This means that we have to look for a critical value in the z table at a 5% level of significance which gives us a value of 1.645.

(a) We are given the confidence level of 99%, so;

     Level of significance = 1 - 99%

                                         = 1 - 0.99 = 0.01 or 1%

Now, = =

This means that we have to look for a critical value in the z table at a 0.5% level of significance which gives us a value of 2.5758.

d

step-by-step explanation:

given

y + 3 = - 4(x - 2) ← distribute the parenthesis

y + 3 = - 4x + 8 ( subtract 3 from both sides )

y = - 4x + 5 → d

85.560%

step-by-step explanation:

conditional probability is defined as:

p(a|b) = p(a∩b) / p(b)

in other words, the probability that a occurs, given that b has occurred = the probability that both a and b occur / the probability that b occurs.

in this example:

p(turns 64 | turns 44) = p(turns 64 & turns 44) / p(turns 44).

if someone turns 64, they must have already turned 44, so:

p(turns 64 | turns 44) = p(turns 64) / p(turns 44)

on page 42, we see that of the original 100,000, 94944 turn 44, and 81234 turn 64.   therefore:

p(turns 64 | turns 44) = 81234 / 94944

p(turns 64 | turns 44) = 0.85560