Question

• For each of the problems that ask if there is a significant difference, state a null hypothesis for that problem.
• Assume that P<0.05 is statistically significant.

1. Sixteen students recently measured the sodium concentration in their sera with the NOVA 5 Analyzer and with the Roche c311 Analyzer.

Student           NOVA 5         c311

     1                      139             137

     2                      142             144

     3                      141             137

     4                      139             139

     5                      144             139

     6                      147             143

     7                      143             136

     8                      144             139

     9                      145             140

    10                     138             138

    11                     141             139

    12                     141             137

    13                     145             144

    14                     142             140

    15                     142             138

    16                     138             135

Is there a statistically significant difference in results between the NOVA 5 method and the c311 method?

What is the basis for your answer?

Answer 1

H0:Null Hypothesis:

HA:Alternative Hypothesis:

From the given data, the following statistics are calculated:

n1 = 16

1 = 141.94

s1=2.6458

n2 = 16

2 = 139.06

s2 = 2.6702

Test statistic is:

t = (141.94 - 139.06)/0.9397 = 3.06

= 0.05

ndf = n1+n2 - 2= 16 + 16- 2 = 30

From Table, critical values of t = 2.0423

Since the calculated value of t = 3.06 is greater than critical value of t = 2.0423, the difference is significant. Reject null hypothesis.

Conclusion:
The data support the claim that there is a statistically significant difference in results between the NOVA 5 method and the c311 method.

The basis of our answer is that the populations of NOVA 5 method and the c311 method are normal distributions.