Question 1

In an experiment,explain the difference between the treatments and the factors.

Accepted Answer

The answer of In an experiment,explain the difference between the...

Question 2

A researcher wants to investigate the effectiveness of a cholesterol-lowering medication.The 450 participants are first divided into two groups - those suffering from diabetes and those not suffering from diabetes.Within each group the participants are randomly assigned to one of three groups.The first group will receive a low dose of the medication,the second group will receive a high dose of the medication,and the third group will receive a placebo.At the end of a six-month period,each person's cholesterol will be tested and the change in their cholesterol level will be recorded.Identify the treatments.

Accepted Answer

The treatments in this study are the placebo, low dose of medication, and high dose of medication. These are the interventions being directly manipulated to observe their effect on cholesterol levels.

Question 3

A manufacturer of tennis rackets has designed a new racket and would like to compare it to their previous design.Suggest an appropriate experiment.

Accepted Answer

The answer of A manufacturer of tennis rackets has designed...

Question 4

A researcher wants to examine the effect of fertilizer and the effect of sunlight on the yield of tomatoes.She bought 60 tomato plants at a local garden store.She randomly assigned 30 tomato plants to be planted on the sunny side of the hill and 30 to be planted on the shady side.The 30 plants which are planted on the shady side are randomly assigned to one of three groups.The first group is grown with no fertilizer,the second group with a small amount of fertilizer,and the third group with a large amount of fertilizer.The 30 plants which are planted on the sunny side are likewise randomly assigned to one of three groups.The first group is grown with no fertilizer,the second group with a small amount of fertilizer,and the third group with a large amount of fertilizer.All tomato plants are planted at the same time and are all treated alike (in terms of how much they are watered,weeded etc.).Each plant is grown to maturity.The total weight of tomatoes obtained from each plant is recorded.

Accepted Answer

The answer of A researcher wants to examine the effect...

Question 5

A researcher would like to investigate whether people suffering from insomnia can be helped by taking regular yoga classes or by reducing their intake of caffeine.Design an appropriate experiment.Be sure to identify the factors,levels,treatments,and response variable.

Accepted Answer

The answer of A researcher would like to investigate whether...

Question 6

A researcher wants to examine the effect of fertilizer and the effect of sunlight on the yield of tomatoes.She bought 60 tomato plants at a local garden store.She randomly assigned 30 tomato plants to be planted on the sunny side of the hill and 30 to be planted on the shady side.The 30 plants which are planted on the shady side are randomly assigned to one of three groups.The first group are grown with no fertilizer,the second group with a small amount of fertilizer,and the third group with a large amount of fertilizer.The 30 plants which are planted on the sunny side are likewise randomly assigned to one of three groups.The first group are grown with no fertilizer,the second group with a small amount of fertilizer and the third group with a large amount of fertilizer.All tomato plants are planted at the same time and are all treated alike (in terms of how much they are watered,weeded etc).Each plant is grown to maturity.The total weight of tomatoes obtained from each plant is recorded.Identify the factor(s)and the number of levels for each.

Accepted Answer

The factors are fertilizer and location, with 3 levels for fertilizer and 2 levels for location. This is a 2x3 design.

Question 7

A researcher wants to examine the effect of fertilizer and the effect of sunlight on the yield of tomatoes.She bought 60 tomato plants at a local garden store.She randomly assigned 30 tomato plants to be planted on the sunny side of the hill and 30 to be planted on the shady side.The 30 plants which are planted on the shady side are randomly assigned to one of three groups.The first group are grown with no fertilizer,the second group with a small amount of fertilizer,and the third group with a large amount of fertilizer.The 30 plants which are planted on the sunny side are likewise randomly assigned to one of three groups.The first group are grown with no fertilizer,the second group with a small amount of fertilizer and the third group with a large amount of fertilizer.All tomato plants are planted at the same time and are all treated alike (in terms of how much they are watered,weeded etc).Each plant is grown to maturity.The total weight of tomatoes obtained from each plant is recorded.Identify the treatments.

Accepted Answer

The treatments are defined by the level of sunlight (sunny or shady) and the level of fertilizer (no fertilizer, small amount of fertilizer, and large amount of fertilizer). Option B correctly identifies all six treatment groups.

Question 8

A researcher wants to investigate whether different forms of exercise can be used to help hyperactive children.A group of 90 children is divided into two groups according to age - those aged 9-12 and those aged 5-9.Within each age group the children are randomly assigned to one of three groups.The first group will just do their normal exercise.The second group will be given an additional exercise routine (moderate).The third group will be given an additional exercise routine (strenuous).At the end of a four month period parents will be asked to evaluate their children's progress.

Accepted Answer

This design is a randomized block design because the participants are divided into blocks based on their age. Within each age group, the participants are randomly assigned to one of the three exercise groups. This design allows for comparison between the different exercise groups while controlling for the potential confounding variable of age.

Question 9

A researcher wants to investigate the effectiveness of a cholesterol-lowering medication.The 450 participants are first divided into two groups - those suffering from diabetes and those not suffering from diabetes.Within each group the participants are randomly assigned to one of three groups.The first group will receive a low dose of the medication,the second group will receive a high dose of the medication,and the third group will receive a placebo.At the end of a six-month period,each person's cholesterol will be tested and the change in their cholesterol level will be recorded.

Accepted Answer

The correct design is a randomized block design where the participants are first blocked into groups based on whether they have diabetes or not, and then within each block, they are randomly assigned to different levels of a single factor, which is the medication dosage (low, high, or placebo).

Question 10

A researcher has developed a set of breathing exercises and would like to investigate whether they can help to reduce anxiety.She wonders whether the breathing exercises for 15 minutes or for 30 minutes would be more effective.Design an appropriate experiment.

Accepted Answer

The answer of A researcher has developed a set of...

Question 11

An exercise physiologist has designed two alternative training regimes which he hopes will enable middle distance runners to improve their times at the 800 metres.He wants to know which regime will work better.Design an experiment which will allow him to investigate this question.Assume that all the athletic coaches in a district are prepared to participate and assume that all athletes training with a particular coach will follow the same regime.Be sure to identify the factors,the levels,treatments,and response variable.

Accepted Answer

The answer of An exercise physiologist has designed two alternative...

Question 12

A researcher would like to investigate whether people suffering from insomnia can be helped by taking yoga classes.She designs an experiment as follows.She will obtain a group of volunteers who are suffering from insomnia and who do not currently practice yoga.Each person's degree of insomnia at the start of the experiment will be evaluated.She will investigate whether yoga classes every day or three times per week are more effective.So the factor yoga will have 3 levels (no yoga,yoga three times a week,yoga every day).Each volunteer will choose which group they would like to be part of.At the end of a suitable time period,for example two months,each person's degree of insomnia will again be evaluated.The improvement for the three groups will then be compared.The person evaluating the insomnia levels will be blinded to which group the patients were in.Identify the flaw(s)in this experiment.

Accepted Answer

The answer of A researcher would like to investigate whether...

Question 13

An education researcher was interested in examining the effect of the teaching method and the effect of the teacher on students' scores on a reading test. Suppose there are four different teachers (Juliana, Felix, Sonia, and Helen) and three different teaching methods (A, B, and C). Students were randomly assigned to a teaching method and teacher. Those who studied with Sonia using method B achieved the highest scores.

Accepted Answer

This is an experiment because the researcher manipulated the teaching method and the teacher and then measured its effect on students' scores on a reading test. Random assignment was also used, which increases the experimental control.

Question 14

An ice cream company wants to introduce a new flavor.They are considering two possibilities - Mint Delight and Chocolate Fiesta.They want to know which one customers will prefer.Design an experiment to investigate this question.

Accepted Answer

The answer of An ice cream company wants to introduce...

Question 15

780 participants suffering from depression were randomly assigned to one of three groups.Over a four-month period,the first group received a low dosage of an experimental drug,the second group received a high dosage of the drug,and the third group received a placebo.At the end of the period each participant rated their mood on a scale of 1-10.Identify the factor(s)in the experiment and the number of levels for each.

Accepted Answer

The answer of 780 participants suffering from depression were randomly...

Question 16

A medical researcher believes that supplements of glucosamine can help to reduce the pain of arthritis.She would like to test the supplement at two different dosage levels.Design an experiment to test the conjecture.Be sure to identify the factors,the levels,treatments,and response variable.

Accepted Answer

The answer of A medical researcher believes that supplements of...

Question 17

A researcher wants to investigate whether different forms of exercise can be used to help hyperactive children.A group of 90 children is divided into two groups according to age - those aged 9-12 and those aged 5-9.Within each age group the children are randomly assigned to one of three groups.The first group will just do their normal exercise.The second group will be given an additional exercise routine (moderate).The third group will be given an additional exercise routine (strenuous).At the end of a four month period parents will be asked to evaluate their children's progress.Identify the treatments.

Accepted Answer

The answer of A researcher wants to investigate whether different...

Question 18

In a clinical trial,780 participants suffering from high blood pressure were randomly assigned to one of three groups.Over a one-month period,the first group received a low dosage of an experimental drug,the second group received a high dosage of the drug,and the third group received a placebo.The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded.The biggest decrease in blood pressure was for those who received the low dosage of the drug.

Accepted Answer

The trial is described as having participants randomly assigned to one of three groups based on the dosage of the drug or a placebo, indicating it is completely randomized over one factor, which is the experimental drug. There is no mention of blocking by diastolic blood pressure or any other factor.

Question 19

Explain the difference between an observational study and an experiment.

Accepted Answer

The answer of Explain the difference between an observational study...

Question 20

780 participants suffering from depression were randomly assigned to one of three groups.Over a four-month period,the first group received a low dosage of an experimental drug,the second group received a high dosage of the drug,and the third group received a placebo.At the end of the period each participant rated their mood on a scale of 1-5.Identify the treatments.

Accepted Answer

The treatments are the different conditions or interventions applied to participants in the study, which in this case are the placebo, low dosage of the experimental drug, and high dosage of the experimental drug.

Quiz 11: Experiments and Observational Studies