How many ways does NASA use pi?

At least 18 according to the Jet Propulsion Laboratory at NASA based on the article for pi day — Oh, the Places We Go: 18 Ways NASA Uses Pi.  Number 12 on the list: Keeping rover wheels turning:

Rover wheels have distinct designs on them that leave patterns on the ground as they turn. These patterns serve as visual markers that help operators while driving the Mars rovers remotely from Earth. Pi is used to calculate how far the rover should travel with each wheel rotation. By measuring the distance from one wheel mark to another, rover drivers can determine if the wheels are slipping or if they’ve driven the expected distance.

Each of the 18 on the list has an associated project with a printable poster. The  Celebrate Pi Day with NASA page has resources for educators, students, and pi day enthusiasts.

0 to 6 or 1 to 7, Does it matter?

The Decoded/Pew Research Center article On a scale from 1 to 10, how much to the numbers really matter? by Jonathan Evans reports on their experiment using a 0 to 6 scale and 1 to 7 scale.

To carry it out, we randomly assigned respondents in France, Germany and the United Kingdom our political ideology question with one of two 7-point scales: either 0–6 or 1–7. The full question wording using our traditional 0–6 scale was this: “Some people talk about politics in terms of left, center and right. On a left-right scale from 0 to 6, with 0 indicating extreme left and 6 indicating extreme right, where would you place yourself?”

Their graph copied here shows the results of this study. An explanation:

These outcomes suggest that when a scale is easily divided in half — for example, when the maximum value is 6 rather than 7 — it’s more likely for respondents to select the midpoint. Previous research has found that respondents are likely to assume that half the top endpoint is a scale’s midpoint, so when half the top endpoint is not an answer option (e.g., 3.5 on the 1–7 scale), respondents seeking the central point on the scale may sometime choose 3 (not the scale midpoint) and sometimes choose 4 (the actual scale midpoint). Those who received the 0–6 scale could more easily find the midpoint (3) by halving the top endpoint.

The article has other charts and links to methodology.

How do we humanize data?

When comparing countries or even within countries, we can talk about GDP, Gini coefficients, poverty rates, etc., but sometimes (all the time?) it is hard to know what this really means for people. If a picture is worth a 1000 words then Dollar Street has 30,000,000 words as they “visited 264 families in 50 countries and collected 30,000 photos” resulting in an excellent example of humanizing data.

The pictures here represent the bathroom for a family in India earning \$4621 per month and for a family in Egypt earning \$775 per month (which is which?).  Dollar Street has large sets  of pictures like this from around the work for over 100 different categories such as armchairs, beds, computers, earrings,  floors, hands, ovens, and plates.  Difference can be explored by picture within countries or the world. These sets of pictures provide both a sense of what poverty is really like around the world, while at the same time there are much more similarities than one might expect even with seemingly large gaps in income. Take the time to visit Dollar Street.

How important are clouds to our climate?

The Quanta Magazine article, A World Without Clouds A state-of-the-art supercomputer simulation indicates that a feedback loop between global warming and cloud loss can push Earth’s climate past a disastrous tipping point in as little as a century by Natalie Wolchover (2/25/19), reports on recent finding published in Nature Geoscience.

Clouds currently cover about two-thirds of the planet at any moment. But computer simulations of clouds have begun to suggest that as the Earth warms, clouds become scarcer. With fewer white surfaces reflecting sunlight back to space, the Earth gets even warmer, leading to more cloud loss. This feedback loop causes warming to spiral out of control.

The simulation revealed a tipping point: a level of warming at which stratocumulus clouds break up altogether. The disappearance occurs when the concentration of CO2 in the simulated atmosphere reaches 1,200 parts per million — a level that fossil fuel burning could push us past in about a century, under “business-as-usual” emissions scenarios. In the simulation, when the tipping point is breached, Earth’s temperature soars 8 degrees Celsius, in addition to the 4 degrees of warming or more caused by the CO2 directly.

There is evidence that this may have happened in the past:

More data points surfaced in China, then Europe, then all over. A picture emerged of a brief, cataclysmic hot spell 56 million years ago, now known as the Paleocene-Eocene Thermal Maximum (PETM). After heat-trapping carbon leaked into the sky from an unknown source, the planet, which was already several degrees Celsius hotter than it is today, gained an additional 6 degrees.

What is the current information on wages trends?

EPI has released its report: State of Working America Wages 2018, Wage inequality marches on – and is even threatening data reliability by Elise Gould (2/20/19). The report includes 19 tables and charts. The data and charts are easily downloaded, such as the chart here. The report is thorough and anyone reading it will likely be surprised about something.  A few selection from the report:

From 2017 to 2018, men at the 95th percentile saw large wage gains, while those at the middle and very bottom of their wage distribution experienced downright wage losses.

The gender wage gap at the 10th percentile remains the smallest across the wage distribution and it has narrowed since 2000; it is currently at 5.9 percent. The regression-adjusted average gender wage gap narrowed slightly from 2000 to 2018 and is currently at 22.6 percent.

In both comparison periods, both men and women at the 10th percentile saw greater wage growth in states with minimum wage changes versus those without.

Over the last 18 years, wage growth for white and Hispanic workers has been about four times faster than that of black workers in the 20th through the 70th percentiles of their respective wage distributions. The 60th and 70th percentiles of the black wage distribution remain below their 2000 levels.

The wages of those with a high school diploma rose faster than the wages of those with a college degree over the last two years, narrowing the gap between college and high school wages. As a result, the college wage premium—the regression-adjusted log-wage difference between the wages of college-educated and high school–educated workers—fell from 50.6 percent to 48.4 percent between 2016 and 2018.

The Interactive Graphs page has two charts on wages.

What do SSPs have to do with modeling climate change?

The CarbonBrief article Explainer How ‘Shared Socioeconomic Pathways (SSP)’ explore future climate change by Zeke Hausfather (4/19/18) provides a detailed overview of modeling future climate change based on future societies:

The SSPs feature multiple baseline worlds because underlying factors, such as population, technological, and economic growth, could lead to very different future emissions and warming outcomes, even without climate policy.

They include: a world of sustainability-focused growth and equality (SSP1); a “middle of the road” world where trends broadly follow their historical patterns (SSP2); a fragmented world of “resurgent nationalism” (SSP3); a world of ever-increasing inequality (SSP4); and a world of rapid and unconstrained growth in economic output and energy use (SSP5).

The graph copied here is the 5th in a series of 8 as the article explains the modeling process. The article is particularly useful for any course that discusses the modeling process.  Most of the charts are interactive and there is also an animated graphic. There are links to data sources that requires setting up an (free) account.

What are the differences in the college aspirations of teens?

Pew reports results of a detailed survey in their article Most U.S. Teens See Anxiety and Depression as a Major Problem Among Their Peers — For boys and girls, day-to-day experiences and future aspirations vary in key ways by Juliana Menasce Horowitz and Nikki Graf (2/20/19). Here, we highlight college aspirations:

Girls are more likely than boys to say they plan to attend a four-year college (68% vs. 51%, respectively), and they’re also more likely to say they worry a lot about getting into the school of their choice (37% vs. 26%). Current patterns in college enrollment among 18- to 20-year-olds who are no longer in high school reflect these gender dynamics. In 2017, 64% of women in this age group who were no longer in high school were enrolled in college (including two- and four-year colleges), compared with 55% of their male counterparts.

There are also differences by parental education and economic class:

Among teens with at least one parent with a bachelor’s degree or higher, as well as those in households with annual incomes of \$75,000 or more, about seven-in-ten say they plan to attend a four-year college after high school. By comparison, about half of teens whose parents don’t have a bachelor’s degree or with household incomes below \$75,000 say the same.

The article has a number of other charts and a detailed methodology section (perfect for a stats  course).

What is the peak quarter for utility revenues?

The question is answered in the Census Bureau post Census Bureau Data Show Third Quarter is Peak Time for Electric and Water Utilities by Justin Jarrett (1/5/19).

During just this year, U.S. electric utility revenue (NAICS 2211) for the third quarter of 2018 was \$137.9 billion, an increase of 20.1 percent (± 2.7 percent) from the second quarter of 2018.

The graph here (copied from the post) has a couple of intriguing peaks between some Q3 years.  Worth noting:

Industries that exhibit seasonal patterns, like electric and water utilities, can mask underlying economic conditions. However, seasonal adjustment produces data in which the values of neighboring quarters are usually easier to compare.

The Census Bureau has the data available on their Quarterly Services page (look under Historical Data tab).

Why should we care about insects?

The Guardian article, Plummeting insect numbers ‘threaten collapse of nature’ by Damian Carrington (2/10/19) reports on the recent Biological Conservation paper Worldwide decline of the entomofauna: A review of its drivers by Francisco Sánchez-Bayo and Kris A.G.Wyckhuys (1/20/19).

More than 40% of insect species are declining and a third are endangered, the analysis found. The rate of extinction is eight times faster than that of mammals, birds and reptiles. The total mass of insects is falling by a precipitous 2.5% a year, according to the best data available, suggesting they could vanish within a century.

(Note percentage rate of change in the quote.) Why?

The analysis, published in the journal Biological Conservation, says intensive agriculture is the main driver of the declines, particularly the heavy use of pesticides. Urbanization and climate change are also significant factors.

So what?

One of the biggest impacts of insect loss is on the many birds, reptiles, amphibians and fish that eat insects. “If this food source is taken away, all these animals starve to death,” he said. Such cascading effects have already been seen in Puerto Rico, where a recent study revealed a 98% fall in ground insects over 35 years.

and

“If insect species losses cannot be halted, this will have catastrophic consequences for both the planet’s ecosystems and for the survival of mankind,” said Francisco Sánchez-Bayo

The Guardian article is a good QL resource. The paper has nice graphs and data but is behind a paywall.

How warm was 2018?

A number of agencies have reported that 2018 was the fourth hottest year on record. The report from NASA GIS, 2018 Fourth Warmest Year in Continued Warming Trend, According to NASA, NOAA (2/6/19) includes a short video showing the warming of the planet while including other facts. The report also includes the animated graph, copied here, with temperature trends from five different agencies.

Global temperatures in 2018 were 1.5 degrees Fahrenheit (0.83 degrees Celsius) warmer than the 1951 to 1980 mean, according to scientists at NASA’s Goddard Institute for Space Studies (GISS) in New York. Globally, 2018’s temperatures rank behind those of 2016, 2017 and 2015. The past five years are, collectively, the warmest years in the modern record.

The post includes a link to data.