A bank wonders if omitting the annual credit card fee for customers who charge at least $2400 in a year will increase the amount charged on its credit cards. The bank makes this offer to an SRS of 200 of its credit card customers. It then compares how much these customers charge this year with the amount that they charged last year. The mean increase in the sample is $332, and the standard deviation is $108.

We reject the H0

Step-by-step explanation:

Given that:

Sample size, n = 200

x, = 332 ; s = 108

H0 : μ = 0

H1: μ > 0

The test statistic :

(x - μ) / s/sqrt(n)

332 / 108/sqrt(200)

332 / 7.6367532

Zstatistic = 43.47

Pvalue from Zstatistic at α = 0.05

P value is bet small < 0.00001

Pvalue < α

We reject the null

Conclusion: Amount charged on credit card under the no - fee plan increases

(n^3 - n)

= n(n-1)(n+1)

since it is divisible by 3 and 2 ,because it is a multiple 3 consecutive number

if, n-1 is odd then n+1 is also odd, then it is a multiple of 9

but if, n-1 is even then n+1 is also even, then it is a multiple of 4

so, largest multiple = max(9*2, 4*3) = max(18, 12) = 18

yes. we do proportions in probabilities.