Question

Quantitative noninvasive techniques are needed for routinely assessing symptoms of peripheral neuropathies, such as carpal tunnel syndrome (CTS). An article reported on a test that involved sensing a tiny gap in an otherwise smooth surface by probing with a finger; this functionally resembles many work-related tactile activities, such as detecting scratches or surface defects. When finger probing was not allowed, the sample average gap detection threshold for m = 8 normal subjects was 1.71 mm, and the sample standard deviation was .53; for n = 10 CTS subjects, the sample mean and sample standard deviation were 2.53 and .87, respectively.

Required:
a. Does this data suggest that the true average gap detection threshold for CTS subjects exceeds that for normal subjects?
b. State and test the relevant hypotheses using a significance level of 0.01.

Answer 1

Hence, data does not suggest the true average gap detection threshold for CTS subjects exceeds that for normal subjects.

Explanation:

H0 : μ1 = μ2

H1 : μ1 < μ2

Given :

m = 8 ; x1 = 1.71 ; s1 = 0.53

n = 10 ; x2 = 2.53 ; s2 = 0.87

The test statistic :

(x1 - x2) / √(s1²/m + s2²/n)

(1.71 - 2.53) / √(0.53²/8 + 0.87²/10)

-0.82 / √0.1108025

Test statistic = - 0.82 / 0.3328700

Test statistic = - 2.463

The degree of freedom using the conservative approach :

Smaller of (10 - 1) or (8 - 1)

df = 7

TCritical value(0.01, 7) = 2.998

Decision region :

Reject H0 if |Test statistic| > |critical value|

Since, 2.463 < 2.998 ; WE fail to reject H0 ; Hence result is not significant at α = 0.01