Standar error A police officer would like to estimate the proportion of petty theft cases that have gone unsolved in a large city. He takes a random sample of 72 petty theft cases and finds 45 of these have gone unsolved. Set up the equation for the 90% confidence interval for p.

Estimate x Crit. value x standard error

0.625± 1.645*0.0571

Step-by-step explanation:

First calculate the estimate as 72 petty cases and 45 are unsolved as follows :

estimate :72/45=0.625

the critical value is given by cumulative probability equal to the  p* (critical probability) as ,

1)compute value for alpha =1-(confidence value /100).

                                           =1-(90/100)=0.1

for critical probability as p*=1 - (alpha/2)=1 -(0.1/2)=0.95

for this critical value is denoted to central area ,

Z(alpha)=1.645

now the standard error :

s=    here p is estimate and q is probability of failure and n is total no of          cases                  

 s=  =0.0571.

20335+282=20617

step-by-step explanation:

1.4

2.3

step-by-step explanation:

the formula for the constant of variation is

y= kx

divide each side by x

y/x =kx/x

y/x =k

we know a and y

1.   y/x = k

4/1 =4

check the other values to make sure they are the same

8/2 = 4   12/3 =4   and 16/4 =4  

the constant of variation is 4

2.   y/x = k

3/1 =3

check the other values to make sure they are the same

6/2 = 3   9/3 =3   and 12/4 =3  

the constant of variation is 3