Identify the following as an observation(O), a hypothesis (H), an experiment (E), or a conclusion (C): During an assessment in the emergency room, a nurse writes that the patient has a resting pulse of 30 beats/min.

For each of the following, indicate if the answer has a positive or negative sign: Two negative numbers are divided.

For each of the following, indicate if the answer has a positive or negative sign: A negative number is subtracted from a positive number.

How can you describe the shape of the distribution of a data set?

For each of the following, indicate if the answer has a positive or negative sign: A positive and negative number are multiplied.

For each of the following, indicate if the answer has a positive or negative sign: Two negative numbers are added.

In 2017 a pollution index was calculated for a sample of cities in the western states using data on air and water pollution. Assume the distribution of pollution indices is unimodal and symmetric. The mean of the distribution was 43.0 points with a standard deviation of 11.3 points.

a. What percentage of western cities would you expect to have a pollution index between 31.7 and 54.3 points?

b. What percentage of western cities would you expect to have a pollution index between 20.4 and 65.6?

c. The pollution index for San Jose in 2017 was 51.9 points. Based on this distribution, was this unusually high? Explain.

Classify the following statements as an observation (O) or a hypothesis (H): A child with a high fever and a rash may have chicken pox.

Classify the following statements as an observation (O) or a hypothesis (H):
Marble statues undergo corrosion in acid rain.

Classify the following statements as an observation (O) or a hypothesis (H): Analysis of 10 ceramic dishes showed that four dishes contained lead levels that exceeded federal safety standards.

Classify the following statements as an observation (O) or a hypothesis (H): The 100-yd dash was run in 9.8 s.

Classify the following statements as an observation (O) or a hypothesis (H): Dinosaurs became extinct when a large meteorite struck the Earth and caused a huge dust cloud that severely decreased the amount of light reaching the Earth.

Classify the following statements as an observation (O) or a hypothesis (H): A patient breaks out in hives after receiving penicillin.

Write the equality and two conversion factors, and identify the numbers as exact or give the number of significant figures for each of the following: Silicon makes up $28.2 \%$ by mass of Earth's crust.