Why did nativists resent and distrust the new immigrants?

A study of 12,000 able-bodied male students at the University of Illinois found that their times for the mile run were approximately Normal with mean 7.11 minutes and standard deviation 0.74 minute. Choose a student at random from this group and call his time for the mile Y. Find P(Y < 6) and interpret the result.

A time-and-motion study measures the time required for an assembly-line worker to perform a repetitive task. The data show that the time required to bring a part from a bin to its position on an automobile chassis varies from car to car according to a Normal distribution with mean 11 seconds and standard deviation 2 seconds. The time required to attach the part to the chassis follows a Normal distribution with mean 20 seconds and standard deviation 4 seconds. The study finds that the times required for the two steps are independent. A part that takes a long time to position, for example, does not take more or less time to attach than other parts. Management's goal is for the entire process to take less than 30 seconds. Find the probability that this goal will be met for a randomly selected part.

A time-and-motion study measures the time required for an assembly-line worker to perform a repetitive task. The data show that the time required to bring a part from a bin to its position on an automobile chassis varies from car to car according to a Normal distribution with mean 11 seconds and standard deviation 2 seconds. The time required to attach the part to the chassis follows a Normal distribution with mean 20 seconds and standard deviation 4 seconds. The study finds that the times required for the two steps are independent. A part that takes a long time to position, for example, does not take more or less time to attach than other parts. What is the distribution of the time required for the entire operation of positioning and attaching a randomly selected part?

The height (in feet) of a certain kind of tree is approximated by

$$h(t)=\dfrac{160}{1+240e^{-0.2t}}$$

where $t$ is the age of the tree in years. Estimate the age of an 80-ft tree.

Halley’s Law states that the barometric pressure (in inches of mercury) at an altitude of $x$ miles above sea level is approximated by

$$p(x) = 29.92e^{-0.2x}\qquad x \ge 0$$

a. If a hot-air balloonist measures the barometric pressure as $20\text{ in}$ of mercury, what is the balloonist’s altitude?
b. If the barometric pressure is decreasing at the rate of $1\text{ in/hr}$ at that altitude, how fast is the balloon rising?

One reason for the increase in human life span over the years has been the advances in medical technology. The average life span for American women from 1907 through 2007 is given by

$$W(t)=49.9+17.1\ln t, \,\, (1\leq t\leq 6)$$

where $W(t)$ is measured in years and $t$ is measured in 20-year intervals, with $t=1$ corresponding to 1907. a. What was the average life expectancy for women in 1907? b. If the trend continues, what will be the average life expectancy for women in 2027 ($t=7$)?

How does your web browser get a file from the Internet? Your computer sends a request for the file to a web server, and the web server sends back a response. For one particular web server, the time (in seconds) after the start of an hour at which a request is received can be modeled by a uniform distribution on the interval from 0 to 3600 seconds. About what proportion of requests are received within the first 5 minutes (300 seconds) after the hour?

A division of Carter Enterprises produces income tax apps for smartphones. Each income tax app sells for $\$ 8$. The monthly fixed costs incurred by the division are $\$ 25,000$, and the variable cost of producing each income tax app is $\$ 3$.

a. Find the break-even point for the division.

b. What should be the level of sales in order for the division to realize a $15 \%$ profit over the cost of making the income tax apps?

(a) Identify two problems of growing cities, (b) How did reformers work to ease these problems?

How did the Industrial Revolution change working conditions for people?

Use the given vocabulary words listed below to create a crossword puzzle. Exchange puzzles with a classmate. Complete the puzzles, and then check each other's answers.

tenement

Jane took 100 mg of a drug in the morning and another 100 mg of the same drug at the same time the following morning. The amount of the drug in her body $t$ days after the first dose was taken is given by

$$A(t)=\begin{cases} 100e^{-1.4t} &, 0\leq t<1\\ 100(1+e^{1.4})e^{-1.4t} &, t\geq 1 \end{cases}$$

a. What was the amount of drug in Jane's body immediately after taking the second dose? After 2 days? In the long run? b.Sketch the graph of $A$.

Use the given vocabulary words listed below to create a crossword puzzle. Exchange puzzles with a classmate. Complete the puzzles, and then check each other's answers.

urbanization