Question

Name that the poor W a lly pre diders Here are tody the plain why the first will remove the data 100 bodohad y 20 to take bee pollen capsules and take place the Follow both groups for five years. by Find 200 w who takeboll a rly Match with woman of the same , one, and occupation who does not take bee pollen. Follow both groups for five years. 15. At a party, there are 25 students over age 21 and 15 students under age 21. You choose at random five of those over 21 and separately choose at random three of those under 21 to interview about attitudes towar alcohol. What is the probability that a certain student at the party will be interviewed?

Answer 1

(14) The first design will produce more trustworthy data because of the following reasons:

(i) It uses randomization to assign individuals to an experimental group.

(ii) It guards against the placebo effect since the individuals can be easily kept unaware of who is on the bee pollen medication and who is not.

(iii) The levels of the factor(controlled independent variable) of the experiment are set by the experimenter whereas in the second experiment, the group on bee pollen is already taking the bee pollen before the experiment starts and thus the factor's effect can't be associated properly with the results.

(15) If one is always chosen from 25 students over age 21 years then, 8 students can be chosen in ways = 10626 x 455 ways

240*

Similarly, if one is always chosen from 15 students less than age 21 years then, 8 students can be chosen in $_{5}^{25}\textrm{C} * _{2}^{14}\textrm{C}$ ways = 53130 x 91 ways

and the no. of ways in which 8 students can be chosen from 25+15=40 students is $_{8}^{40}\textrm{C} =$ 76904685

Hence, probability of the combined event will be (10626*455 + 53130*91)/76904685

= 0.1257

[Note: all the combination values are calculated by using excel function " =combin"]