World population is growing 20 million people every 3 months

[UAEguy]

Originally Posted by StuM

I've got 200 bags of wet sand each of which weigh between 20 and 40 Kg. I record the weigh of each bag to the nearest Kg.

When I add the weights together I come up with a total of 6138 Kg.

What is the margin of error on that total at a 95 and 99.7% confidence level? (You should be able to work that out from your Statistics for Dummies book. Note, you are not working here with "samples", you are working with multiple "measurements". Even though each bag's weigh is only known to +/- 2.5 to 5%, the final MoE is a LOT less than 3% (180Kg).)

After those bags have been sitting in the sun for a day, I weigh them again. Next day, I do it again. I repeat this every day for a month

At the end of the month, I plot the daily total weights and derive a best fit curve. How accurately can I determine the rate at which the roughly 600 Kg of sand have lost water through drainage and evaporation?

Still failing to address the question...but keep going. Ask some of your IT buddies.

[UAEguy]

Let me help you out...

In your example you knew for a fact that you were measuring "all" of the mass every time you measured.

[UAEguy]

From the UN 2015 World Population Report

World and Regional Totals: Regional population totals are independently
rounded and include small countries or areas not shown.
Regional and world rates and percentages are weighted averages
of countries for which data are available. For most indicators,
regional averages are shown when data or estimates are available
for at least three-quarters of the region’s population.

World Population Data Sheets from different years should not be
used as a time series. Fluctuations in values from year to year
often reflect revisions based on new data or estimates rather than
actual changes in levels. Additional information on likely trends
and consistent time series can be obtained from PRB, and are
also available from UN and U.S. Census Bureau publications and
websites.

[valhalla360]

Originally Posted by UAEguy

Let me help you out...

In your example you knew for a fact that you were measuring "all" of the mass every time you measured.

Then weigh 100 bags and run the same calculations. (you haven't measured ALL the mass)

You haven't weighed all the bags but you will find it's a pretty good estimate.

[Group9]

When it comes to polling, I don't see how anyone can brush off how wrong the pollsters sampling errors have turned out to be. I.E. Brexit, the 2016 election.

Kind of hard to trust them after those whoppers.

[SV THIRD DAY]

Originally Posted by Group9

When it comes to polling, I don't see how anyone can brush off how wrong the pollsters sampling errors have turned out to be. I.E. Brexit, the 2016 election.

Kind of hard to trust them after those whoppers.

Polls are used today to Push an Agenda, not report on it.
Once you understand that, all the polls you see start to make sense (including the poll questions THEY don't ask!)

[a64pilot]

Originally Posted by SV THIRD DAY

Polls are used today to Push an Agenda, not report on it.
Once you understand that, all the polls you see start to make sense (including the poll questions THEY don't ask!)

Like "do you beat your wife often" Remember only yes or no answers

[UAEguy]

Originally Posted by valhalla360

Then weigh 100 bags and run the same calculations. (you haven't measured ALL the mass)

You haven't weighed all the bags but you will find it's a pretty good estimate.

Good estimate of what????

[UAEguy]

This is my favorite line from the UN report:

Many measures presented here are relative errors, such as the percentage error (PE) or the absolute percentage error (APE). PE is defined as

PE=100.(forecast-observation)/observation.

In other words, we determine our error based on a "our own projection" and how incorrect our "count" is relative to that "projection"

[K_V_B]

Originally Posted by UAEguy

Let me help you out...

In your example you knew for a fact that you were measuring "all" of the mass every time you measured.

Let me help you:

A margin of error of X does not mean that all the measurements are off by X. Hence when summing measurements you should not sum the margins of error.
If you sum 100 measurements with a margin of error of X the result will have a margin of error significantly below X.

[SV THIRD DAY]

Since we are in the helping out mode here.....
What was this thread about anyway?

[UAEguy]

Originally Posted by K_V_B

Let me help you:

A margin of error of X does not mean that all the measurements are off by X. Hence when summing measurements you should not sum the margins of error.
If you sum 100 measurements with a margin of error of X the result will have a margin of error significantly below X.

Still missing the point...

[UAEguy]

Originally Posted by SV THIRD DAY

Since we are in the helping out mode here.....
What was this thread about anyway?

Good question.

[Group9]

Originally Posted by SV THIRD DAY

Since we are in the helping out mode here.....
What was this thread about anyway?

Too many people. Some of us are going to have to volunteer to leave early. Any volunteers?

[SV THIRD DAY]

Originally Posted by Group9

Too many people. Some of us are going to have to volunteer to leave early. Any volunteers?

BINGO....and now you understand the motives behind the Progressive movement and Margaret Sanger. The "weeds" needed to be pulled out of the human population pool. It also helps you understand the MMGWC's push and the ZGM (Zero Growth Movement) desire to keep the 3rd world poor and from developing and raising the standard of living for the worlds poor...