MATH 1040 Statistics for Laboratory Sciences

MATH 1040 Statistics for Laboratory Sciences

Review Questions Answers

Question 1

• Self-selected sample; matched pairs
• H0: md = 0; H1: md < 0 xss=removed>
• P-value = 013 < 0>H0; the oat bran diet is effective in reducing cholesterol

Question 2

Control sample cant be assumed to have come from Normal distribution; use Kruskal-Wallis

H0: All medians are equal; H1: Not all medians are equal; a= 0.05

P-value = 0.116 > 0.05 so cant reject H0

Question 3

• H0: Nutritional status and illness are independent; H1: Nutritional status and illness are dependent; a =05.

• All expected counts are ?3;5; P-value = 000 < 0>H0.

• g. no illness and normal diet status shows higher than expected count

Question 4

H0: p1 p2 = 0; H1: p1 p2 ?1;0; a= 0.05

P-value = 0.002 < 0>H0. Difference in proportions is statistically significant at 5% level. Surgery appears to be better.

Question 5

• Check Normality and standard deviations

• H0: All means are equal; H1: Not all means are equal; a= 05

• P-value = 229 > 0.05 so cant reject H0

• Specific age range, specific location

Question 6

• Two independent samples, both come from Normal populations so use two-sample t-test

• H0: m1 m2 = 0; H1: m1 m2 < 0 a=05>
• P-value = 019 < 0>H0; men score lower than women on average.

Question 7

Odd ratio = 11.85

Question 8

• P-value = 000 < 0>
• Average rate of increase in systolic blood pressure with age
• 46 0.2314
• P-value = 000 < 0>
• Excellent fit; 8% of variability in systolic explained by age
• 95% PI is (151.119, 165.291). Prediction accurate since (i) R² indicates excellent fit; (ii) Margin of error is small relative to fitted value; (iii) Prediction is by interpolation

Question 9

H0: Median = 0; H1: Median ?1;0; a= 0.10

P-value = 0.1797 > 0.10 so cant reject H0; not enough evidence to conclude there is a difference in hunger rating.

Question 10

• Check Normal probability plots and standard deviations

• H0: All means are equal; H1: Not all means are equal; a= 0.05; P-value = 0.02 < 0>H0.

• None (diet with no added fat) is different from the others; no significant difference between the two diets with added fat.

• All aged 12, from the same

Question 11

0.3783, so low study power.

Question 12

• Yes
• On average, metabolic rate increases by 25.19 calories for every extra kg in lean body mass. On average, the metabolic rate is expected to be 187 calories with 0 kg in lean body mass (not possible). Lean body mass explains 75.2% of variability in metabolic rate.
• Some evidence of unequal
• Slope estimate is significant, P-value < 05>
• Intercept estimate is not significant, P-value > 0.05. It would make sense to fit a no- intercept model.
• Use confidence Prediction should be reasonably accurate.