Biostatistics Exam Questions PDF

# Statistics Questions ## Question 1 An asymmetry index of -0.3 tells us that: 1) The curve is not symmetrical 2) It has a negative skew 3) The mean is a biased centrality index 4) The median is a centered index 5) All of the above are correct **Answer:** 5 ## Question 2 Indicate an unbiased e...

# Statistics Questions ## Question 1 An asymmetry index of -0.3 tells us that: 1) The curve is not symmetrical 2) It has a negative skew 3) The mean is a biased centrality index 4) The median is a centered index 5) All of the above are correct **Answer:** 5 ## Question 2 Indicate an unbiased estimator of the population mean, if the distribution is asymmetric: 1) Mean 2) Mode 3) Median 4) Variance 5) Options 1, 2, and 3 are correct **Answer:** 3 ## Question 3 What is the minimum variance estimator of the population mean?: 1) Mean 2) Mode 3) Median 4) Range 5) Mean deviation **Answer:** 1 ## Question 4 The standard deviation of a sample distribution of means is called: 1) Range of the mean 2) Standard error of the mean 3) Sample variance 4) Coefficient of variation 5) None are correct **Answer:** 2 ## Question 5 The standard error of the mean is: 1) A statistic of dispersion 2) The standard deviation of a sample distribution of means 3) The distance from the population mean to the point of inflection of the curve 4) It serves to estimate means 5) All of the above are correct **Answer:** 5 ## Question 6 The standard error percentage is: 1) A statistic of dispersion 2) The standard deviation of a sample distribution of percentages 3) The distance for the population percentage to the point of inflection of the curve 4) It serves to estimate percentages 5) All of the above are correct **Answer:** 5 ## Question 7 The standard deviation of a sample distribution of a statistic is called: 1) Coefficient of variation 2) Systematic error 3) Standard error 4) Variance 5) Standard or typical deviation **Answer:** 3 ## Question 8 The interval Sample Mean ± 1.96 EEM (Standard Error of the Mean): 1) It does not say much. 2) It covers 95% of the times the population mean. 3) It covers 99% of the times the population mean. 4) It gives a security of 68%. 5) It gives a security of 5%. **Answer:** 2 ## Question 9 The interval Sample Mean ± EEM (Standard Error of the Mean) 1) Is never used 2) It covers 99% of the times the population mean 3) It covers 95% of the times the population mean 4) It gives a security of 99% 5) It's all false **Answer:** 5 ## Question 10 The interval Sample Mean ± EEM (Standard Error of the Mean): 1) It covers the population mean 68% of the times 2) It doesn't cover the population mean less than 32% 3) The security that the population mean is in such interval is 68% 4) It's not used because the probabilities of failure are too high 5) All of the above are correct **Answer:** 5 ## Question 11 The minimum security required for any mean estimation is: 1) 68% 2) 95% 3) 99% 4) 5% 5) 1% **Answer:** 2 ## Question 12 The maximum allowable error probability in parameter estimation is: 1) < 68 2) < 5% 3) < 1% 4) < 0.01 5) Options 3 and 4 are correct **Answer:** 2 ## Question 13 The minimum allowed error probability in parameter estimation is: 1) < 68% 2) 5% 3) < 1% 4) < 0.1% 5) There is no **Answer:** 5 ## Question 14 We read in an article that the average blood glucose is 110 mg/dl ±10 mg/dl. p<0.01. 1) The sample result is 110 + 10. 2) The security is higher than 99%. 3) The population blood glucose will be between 10 and 120, with absolute certainty. 4) The standard error of the mean is 10 mg/dl. 5) None of the above are correct. **Answer:** 5 ## Question 15 The average blood pressure is 90 ± 5. p<0.05: 1) The sample mean is 90. 2) The population mean is between 85 and 95, with 95% security. 3) The population mean is between 85 and 95 with a probability of making a mistake less than 5% 4) The EEM is 5/1.96 5) All of the above are correct. **Answer:** 5 ## Question 16 If the null hypothesis is true and you accept it: 1) It's the level a. 2) It's the test power. 3) It's type I error. 4) It's 1-a. 5) It's the complement of 1 - b. **Answer:** 4 ## Question 17 If the null hypothesis is true and you reject it: 1) You don't know the probability of it occurring. 2) It doesn't matter. 3) The probability is 1 - a. 4) It never happens. 5) It's type I error. **Answer:** 5 ## Question 18 Clonidine is effective in 87%. Diltiazem is 80%. The differences are not statistically significant, p<0.01: 1) The difference found in the study may be due to chance. 2) There is not enough evidence to say which one is better. 3) Clonidine and Diltiazem may be equally effective despite the results observed. 4) Clonidine may be better than Diltiazem, but we don't have enough evidence to confirm it. 5) All of the above are correct. **Answer:** 5 ## Question 19 Surgery is effective in 90%. Medication is effective in 80%. Statistically significant differences with p<0.05: 1) The null hypothesis states that both are equally effective. 2) The alternative hypothesis states that the two types of treatment are not equally effective. 3) If the null hypothesis were true, there is less than a 5% probability of concluding that one treatment is better than the other. 4) By stating that the two treatments are not equal, there is less than a 5% probability of being wrong. 5) All of the above are correct. **Answer:** 5 ## Question 20 Given an experimental design and a fixed hypothesis test, if you increase the sample size: 1) It increases the probability of error a and b. 2) It decreases the probability of error a and b. 3) It increases the probability of error a. 4) It decreases the probability of error b. 5) It increases the probability of error a and decreases the probability of error b. **Answer:** 4 ## Question 21 If you want to perform a hypothesis test, which of the following situations is better: 1) a = 0.05 and b = 0.05 2) a = 0.05 and b= 0.10 3) a = 0.01 and b = 0.05 4) a = 0.01 and b = 0.10 5) a = 0.01 and b = 0.01 **Answer:** 5 ## Question 22 If Ho is true and you accept it: 1) The probability is 1-a. 2) The probability is set by the researcher. 3) It uses a minimum interval of 95%. 4) It's the size of the hypothesis test. 5) All of the above are correct. **Answer:** 5 ## Question 23 Type II error or beta error is the probability of: 1) Rejecting Ho when it is true. 2) Accepting Ho when it is true. 3) Rejecting Ho when it is false. 4) Accepting Ho when it is false. 5) Options 1 and 3 are correct. **Answer:** 4