PS NOS Less 3

In the case study of the Minneapolis I-35W bridge collapse, what hypothesis was tested by the analysis shown here?

• the hypothesis that the bridge collapsed because it was overloaded

• the hypothesis that the bridge collapsed because gusset plates failed

• the hypothesis that not all gusset plates were the same thickness

• the hypothesis that horizontal loads were greater than vertical loads

A video of the collapsing bridge was useful for which part of the scientific investigation in the case study?

• observation

• modeling

• hypothesis testing

• drawing conclusions

Which of the following is qualitative data collected during the investigation into the I-35W bridge collapse?

• Concrete added to the bridge in 1977 increased the load on the bridge by 13.4%

• Due to renovation equipment, another 20% load increase was on the bridge when it collapsed.

• Concrete and other materials had been added to the bridge after its original construction.

• Additional renovation done on the bridge in 1998 increased the load on the bridge by 6.1%.

In order to investigate whether hot water helps plants grow faster, a student gives 12 plants room-temperature water once a week, and 12 other plants hot water once a week. Which statement is true?

• All of the plants are in the control group, and there is no experimental group.

• The plants getting hot water are the experimental group, and the plants getting room-temperature water are the control group.

• The plants getting hot water are the control group, and the plants getting room-temperature water are the experimental group.

• All of the plants are in the experimental group, and there is no control group.

In an experiment comparing the growth rate of plants given hot water to the growth rate of plants given room-temperature water, what is the dependent variable?

• the number of plants in each group

• the type of liquid given to the plants

• the sizes of the plants at the beginning of the experiment

• the rate of plant growth