Name 1 problem or missing component for each of the followin

Name 1 problem or missing component for each of the following experiments. a. In many reptiles, sex is determined by the incubation temperature of the egg where higher temperatures lead to more males. However, DDE (a chemical byproduct of DDT) in the environment prior to birth drastically lowers the normal percentage of males. You place 2C reptile eggs in an incubator set at 40 degree C and spray them with DDE. You place 20 eggs at room temperature and spray them with water. After they hatch, you record the number of males from each group. b. You are studying the effects of artificial sweetener on cancer rates in mice. One mouse consumes one packet of sweetener a day for 4 months. A second mouse consumes 2 packets, a third 3 packets and a fourth 4 packets a day for 4 months. A fifth mouse consumes one packet of regular sugar. c. A new nutritional supplement alleges that both men and women can lose weight without dieting and exercise. A total of 50 people were divided into 2 groups with group 1 being 25 women and group 2 being 25 men. Both the men and women were between the ages of 18 and 35, in good health and between 20-40% overweight. They were all weighed at the beginning of the study. Group 1 was asked to take 2 nutritional pills per day while group 2 took 2 placebos per day. At the end of 4 weeks, everyone was weighed again. d. Your roommate exhibits a particular ritual before each exam she takes because she is convinced that this ritual ensures her success on exams. She cats the same meal the night before, goes to bed at exactly the same time, listens to the same song the morning of the exam and always wears the same t-shirt to the exam. She scores a 92% on her first Biology exam. For exam U2, 35 people from her Biology class follow her ritual and score As as well!

Solution

Ans. A.

Part I: 20 eggs at 40⁰C + spayed with DDE          - Tests elevated temperature affects sex ratio or not?

Part II: 20 eggs at 20⁰C + spayed with water.      - Serves as control at 20⁰C

Another control (Part III: 20 eggs at 40⁰C + spayed with water) is required. It shows the effect of high incubation temperature (excluding the effect of DDE). When compared with the results obtained in part I, it shall determine the effect of DDE on reducing male ratio.

Ans. B.

1. Mouse I        – 1 packet artificial sweetener per day – for 4 months

2. Mouse II       – 2 packet artificial sweetener per day – for 4 months

3. Mouse III      – 3 packet artificial sweetener per day – for 4 months

4. Mouse IV      – 4 packet artificial sweetener per day – for 4 months

5. Mouse V       – 1 packet regular sugar per day – for 4 months = parallel to 1

Missing: A. Mouse V shall be fed for 4 months, too.

            B. A parallel experiment shall be set up in control group. That is, -

6. Mouse VI- 2 packet regular sugar per day – for 4 months         = parallel to 2

Similarly, set up parallel to 3 and 4, too.

By running parallel studies, we can assess –

effect of artificial sweetener vs regular sugar on cancer rates

effect of amount of artificial sweetener on cancer rates – to test if higher intake of artificial sweetener increase cancer risk or the risk persists at all doses.

Ans. C.

Given: Group 1: 25 women. 2 nutritional pills per day.

            Group 2: 25 men. 2 placebo pills per day.

Missing: A. Placebo group for females ; and B. Nutritional pill group for men.

The men and female bodies may exhibit significantly different responses to certain diets and placebo effects.

So, a control (placebo) group consisting of 25 women of same age group and weight criteria be set up parallel to group 1. Similarly, a nutritional pill group for men shall be set up against group 2.

Ans. D.

Missing: 1. Total number of students in the class. Only 35 of which followed the rituals.

            2. The score % of your roommate in exam#2.

            3. The score % of other students following the rituals in exam#2.

            4. The score % of other students NOT following the rituals in exam#2.

Comparison of 3 and 4 gives a better overview of effect of rituals on scoring marks.