Question

New York Police have been criticized in the media recently for being extraordinarily slow to respond to domestic violence calls. The Head of New York City Council cited the New York Times data in a public meeting and announced:

"As anyone can plainly see New York Police have done a terrible job. We need to act immediately to improve response times."

A. State the Null Hypothesis

B. Enter value of the test statistic

C. Enter Critical Value

D. Enter P value

Dispatch Policy Change Before After 12 26 14 11 19 18 22 32 18 31 26 9 36 10 28 12 19 32 14

Answer 1

Let the significance level be 0.05

A.

Null Hypothesis(H0): The response time has not decreased significantly after the dispatch policy change, i.e., no improvement.

After population mean - Before population mean $\geq$ 0.

B.

The test statistic value, t = -0.42

Dev (Diff M) Diff(T2-T1) Sq. Dev Treatment 1 Treatment 2 14 16 256 26 -3 -1 1 14 11 -1 1 19 18 10 12 144 22 32 18 13 15 225 31 19 17 361 9 26 -26 -24 576 36 10 -14 28 -16 196 12 -10 -8 64 19 9 -18 -16 256 32 14 S: 2080 M:-2 N a N Co

Difference Scores Calculations Mean: -2 S2= SSdf= 2080/(10-1) 231.11 S2M S2/N= 231.11/10 23.11 SM= VSM V23.11 4.81 T-value Calculation t = (M- H)/SM (-2 - 0)/4.81 -0.42

C.

Degrees of freedom, df =n - 1 =10 - 1 =9

Significance level =0.05

Type of test =left tailed (One-tailed)

So, the critical value of t = -1.83

D.

At df =9, for t = -0.42, for one-tailed test, the P-value =0.34​​​​​​