Analyzing Evidence Answers

Medical researchers often test medicines on patients who have given informed consent for the tests. The researchers divide the patients into two groups. One group is given the medicine. The second group is given a harmless substitute such as sugar pills. Neither the patients nor the researchers know which patients have received the medicine and which have received the substitute. What is the purpose of having neither the patients nor the researchers know who is receiving which treatment?

In which way could the results of an experiment have bias?

Which part of a scientific argument must be supported by valid data?

Yannick’s class measured the width of one leaf several times. The values that the class recorded included 10 mm, 8 mm, 15 mm, 5 mm, and 13 mm. What is lacking from the measurements that the class made?

Scientific evidence is most likely to be consistent if it is based on data from

Penny measured the time that it took her rat to run through a maze. She conducted the experiment 10 times and recorded the set of data below.Times: 67 s, 69 s, 68 s, 66 s, 78 s, 70 s, 67 s, 69 s, 68 s, 66 sWhich time is most likely an outlier?

The scientific evidence that scientists use in supporting or critiquing the conclusions of experiments usually consists of

Cory recorded the following values when he measured the length of leaves from one tree.Length in centimeters: 10, 13, 11, 12, 12, 11, 8What is the mean of Cory’s data?

A scientific argument will be considered invalid if the evidence supporting that argument is based on

Some kinds of data can be summarized in an illustration. The illustration below shows plant zones on a tall mountain. Assume that the plants shown are accurately drawn to scale.Which statement best summarizes a trend that is shown in the illustration?

Dawn recorded her measurement of the mass of a sample of leaves as 13 grams (g). Four of her classmates measured the same sample and recorded the following data: 30 g, 31 g, 29 g, and 30 g. All students used the same balance during the same class period. Dawn’s data are most likely inconsistent due to

To critique scientific arguments and increase the validity of scientific evidence, scientists

One way to get consistent, valid data is to

Doctors report incidences of illness, such as influenza, to the Centers for Disease Control (CDC). The graph below shows data for three years. Note that this graph shows from October of one year to October of the following year. The leftmost data on the graph begins with week 40 (October) and shows data through the end of the year. The tick mark for week 1 (beginning of January) is roughly in the middle of the x axis. One journal said that influenza trends in 2008-09 were unusual. Based on the evidence in the graph, what range of data did the journal most likely use to support the claim?