In December 2004, a report based on the National Survey on Drug Use and Health estimated that 20% of all Americans aged 16 to 20 drove under the influence of drugs or alcohol in the previous year. We would like to update this information by calculating a 98% confidence interval. How large a sample is necessary in order for the bound on the error of estimation to be 0.04?

542

Step-by-step explanation:

We are required to find the sample size at 98% confidence interval in this question

E = 0.04

P* = 20% = 0.20

n = p* x (1-p)(Zα/2÷E)²

α = 1 - 0.98

= 0.02

To get Critical value

= 0.02/2 = 0.01

The critical value at 0.01 is 2.33

Inserting values into formula:

O.2 x 0.8(2.33/0.04)²

= 0.8 x 0.2 x 58.25²

= 542.89

The value of n must be an integer therefore the answer is 542.

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for