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10. The data below is to compare of peak expiratory flow rate (PEFR) before and

ID: 3371234 • Letter: 1

Question

10. The data below is to compare of peak expiratory flow rate (PEFR) before and after a walk on a Subiect Before After 1 312 300 2 242 201 3 340232 4 388 312 5 296 220 6 254 256 7 391 328 8 402330 cold winter's day for a random sample of 9 asthmatics.940231 For differences between PEFR Before and PEFR After, the data summary is given below. Mean of differences 56.11and the standard deviation 34.173983. Whether there is sufficient evidence that the average PEFR Before is significant different from PEFR After. Test statistic-

Explanation / Answer

Test statistic = Mean(Xd) / (Sd / n0.5 )

where , Mean(Xd) = Mean of differences = 56.11

Sd = standard deviation = 34.173983

n = sample size = 9

Test statistic = Mean(Xd) / (Sd / n0.5 ) = 56.11 / ( 34.173983 / 90.5) = 4.92567

Test statistic = 4.92567

The degrees of freedom (d.f ) of the reference t-distribution = n - 1 = 9 - 1 = 8