State whether the following statement is true or false, and explain why. If a statement is false, state the true change. A high school reports that its students' SAT scores were down by $10 \%$ in one year. The next year, however, SAT scores rose by $20 \%$. The high school principal announces, "Overall, test scores have improved by $10 \%$ over the past two years."

Find out the absolute change and the relative change in the following case. The number of refugees in the world increased from $8.7$ million in $2005$ to $16.1$ million in $2015$.

The following table shows real arrival data for two airlines in five cities (airline names have been changed).

Source: Technical Review $(1994)$, p. $3845$.

a. Which airline has the higher percentage of on-time flights to the five cities?

b. Compute the percentage of on-time flights for the two airlines over all five cities.

c. Explain the apparent inconsistency in these results.

The scores on a psychology exam were normally distributed with a mean of $67$ and a standard deviation of $8$. A failing grade on the exam was anything $2$ or more standard deviations below the mean. What was the cutoff for a failing score? Approximately what percentage of the students failed?

What do we mean by the variation of a distribution? Give simple examples of distributions with different amounts of variation.

Find two power series solutions of the given differential equation about the ordinary point x=0. $y^{\prime \prime}-3 x y=0$

The Greenland ice sheet contains about $3$ million cubic kilometers of ice. If completely melted, this ice would release about $2.5$ million cubic kilometers of water, which would spread out over Earth's $340$ million square kilometers of ocean surface. How much would sea level rise?

The following pairs of investment plans are identical except for a small difference in interest rates. Compute the balance in the accounts after $10$ and $30$ years. Discuss the difference.

Jose invests $\$ 1500$ in an account that earns $5.6 \%$ compounded annually. Marta invests $\$ 1500$ in a different account that earns $5.7 \%$ compounded annually.

The following pairs of investment plans are identical except for a small difference in interest rates. Compute the balance in the accounts after $10$ and $30$ years. Discuss the difference.

Chang invests $\$ 500$ in an account that earns $3.5 \%$ compounded annually. Kio invests $\$ 500$ in a different account that earns $3.75\%$ compounded annually.

The Monk and the Mountain. A monk set out from a monastery in the valley at dawn. He walked all day up a winding path, stopping for lunch and taking a nap along the way. At dusk, he arrived at a temple on the mountaintop. The next day the monk made the return walk to the valley, leaving the temple at dawn, walking the same path for the entire day, and arriving at the monastery in the evening. Must there be at least one point along the path that the monk occupied at the same time of day on both the ascent and descent? (Source: The Act of Creation, Arthur Koestler)

How much must you deposit today into the following accounts in order to have a $\$ 120,000$ college fund in $15$ years? Suppose that no additional deposits are made. An APR of $5.5 \%$, compounded annually

Which tracing in a normal ECG is the repolarization of the atria?

The Greenland ice sheet contains about $3$ million cubic kilometers of ice. If completely melted, this ice would release about $2.5$ million cubic kilometers of water, which would spread out over Earth's $340$ million square kilometers of ocean surface. How much would the sea level rise?

Assuming boys and girls are equally​ likely, find the probability of a couple having a baby boy when their fifth child is​ born, given that the first four children were all boys