







Predicting the number of fish in a lake 
20180916 

April pose la question : A researcher catches 30 fish in a pond, attaches a marker to their fin and releases them. The next day she places a large net in the water and catches 9 fish. 3 have the marker attached to their fin. Can she predict the number of fish in the pond???
Thank you Penny Nom lui répond. 





The square root of a large number 
20100119 

darlene pose la question : I understand the simple process, like 12 is the root to 144 but what happens when the number is 42563. Without a calculator how does a person figure this out during a timed test? Robert Dawson lui répond. 





Fertilizer in a bin 
20090203 

Todd pose la question : Hello I am looking for a formula to figure out the fertilizer volume in a hopper bottom bin not only when it is full but part full as well. When you are filling it is heaped up in the middle to make a cone and when you are emptying the bin the cone is inverted so it would be nice to be able to quickly figure out the tonnes partly filled and when full.
Lets say the bin is 32 feet high from top of bin where you fill to the bottom where the product goes out and it is 16 feet in diameter. I know how to calculate the cylinder it is the cones on the top and bottom of the bin I have the main question on. Harley Weston lui répond. 





Estimate the cube root of 270 
20080311 

Tom pose la question : (a) By plotting suitable graphs, estimate to one decimal place the cube root of 270.
(b) With reference to your answer to part (a), use 8 iterations of a Bisection Search to refine your estimate. Use the nearest whole numbers either side of your estimate from part (a) as starting values.
(c) Using either of your starting values from part (b) as first guess, use the NewtonRaphson method to find the true value of the root (to 6 decimal places). Repeat using the other starting value from part (b) and compare the two results. Harley Weston lui répond. 





How many M&Ms are in a container? 
20061101 

Jill pose la question : How do we algebraically figure out how many M&Ms are in a container? Stephen La Rocque and Penny Nom lui répond. 





Estimating products by rounding 
20060924 

Ann pose la question : my son is in the fifth grade and they are doing estimate products rounding both factors, he knows how to round off a decimal, but he is having a problem doing a decimal and a whole number for example 5.96x3=? He knows the 5.96 round off to 6. but what does the 3 round off to? Penny Nom lui répond. 





A sample size estimation 
20051203 

Ivonne pose la question : I have to do a research about the behavior of library users. We are going to apply a survey to a population of 1280 students (Management an Economics students) but of course we have to do it to a sample....I need to know the size of my sample. Penny Nom lui répond. 





How many digits? 
20050607 

Floren pose la question : The numbers 2^{1989} and 5^{1989} are written one after another. How many digits in all are there? Claude Tardif lui répond. 





50^99 and 99! 
20050523 

Romel pose la question : Which number is greater, 50^{99} or 99! Claude Tardif lui répond. 





Which is smaller 2^175 or 5^75? 
20050518 

Sarah pose la question : Which is smaller 2^{175} or 5^{75}? without using a calculator. Claude Tardif lui répond. 





Making a windmill 
20040102 

Matthew pose la question : I am a farmer in Ontario. It has been almost 20 years since high school. I am toying with making a windmill. The output chart for the the old generator I have is shown below. Before I tear it appart I would like to develop a formula from the chart that can predict the output at various speeds. Penny Nom lui répond. 





How do you estimate the equation of a parabola? 
20021201 

Audrey pose la question : How do you estimate the equation of a parabola? I have a project where a must find parabolas in magazines and then estimate their equation. Penny Nom lui répond. 





x^{ 4} + x^{ 5} = 100 
20021027 

Bill pose la question : One of my students has stumped me. He asked how to solve the equation 4^{ x} + 5^{ x} = 100 All I can think of are graphing methods to get an approximate solution. What am I missing? Harley Weston lui répond. 





Dan is 4 inches taller than Mike. 
20020904 

A parent pose la question : Dan is 4 inches taller than Mike. Together they are 8 feet 8 inches tall. How tall is each boy in feet and inches. Penny Nom lui répond. 





A sample size problem 
20011028 

Charles pose la question : The U.S Transportation Dept. will randomly sample traffic reports to estimate the proportion of accidents involving people over the age of 70. The Dept. has no advance estimate of this proportion. how many reports should the dept select to be atleast 97% confident that the estimate is within .01 of the true proportion? Harley Weston lui répond. 





Linear regression 
20010801 

A student and a mother pose la question : My mom is taking a correspondence course in Simple Linear Regression and Correlation Analysis and we've been arguing about the relationship between the correlation rxy and standard estimate of errorSy.x. I took statistics last year in high school and I remember something about the Sy.x being proportionate to the r. Are they inversely related, directly related, not related, or can only range from 0 to 1.00? Her book doesn't say very much and I believe they are inversely related. She says they're directly related. Chris Fisher and Penny Nom lui répond. 





A confidence interval 
20010426 

Kim pose la question : A poll asked 1528 adults if they were in favor of the death penalty, 1238 said yes, find 99% confidence level for percent of all adult who are in favor of the death penalty. Andrei Volodin lui répond. 





Estimating the time to complete a job 
20001203 

Jack Hook pose la question : I'm a contractor and need to estimate how much time it will take me to do a specific job. A previous job I did was 6,480.16 Square Feet and I was able to paint it in 31.5 hours. In estimating my next job, how many hours will it take me to paint 11,000 Sqare Feet. Penny Nom lui répond. 





Estimates 
20000411 

Sue Jordan pose la question : I am looking for examples of estimates for underestimating and overestimating. When would you do each one. For my child age 11 6th grade. Penny Nom lui répond. 





Number sense 
20000217 

A college student pose la question : I am a college student and I am to answer the following question: Describe ways of telling by simple inspection when a fraction has a value close to 0; close to 1/2; and close to 1. I am to imagine that I am a 3rd grader answering this question. Any thoughts please? Penny Nom lui répond. 





Estimating the population mean 
19991113 

John Barekman pose la question : Statitistics: Estimating the population mean when the standard deviation is known: I am not sure which n to use in the formula for the confidence interval equation: x +/ z*(standard deviation/sqrt(n)) If we have data of ten people, and if we have the data of ten sets of ten people each, what is the difference in the n that we use? What is the difference between the standard deviation and the standard error? Are we using the number of sampling means or just the number of samples? Harley Weston lui répond. 





The bricklayers formula 
19981124 

Rachel Kaplan pose la question : I have to do a report on the bricklayers formula N = 7LH. Can you give me any information on this. Harley Weston lui répond. 





Approximating roots. 
19961104 

Ben Dixon pose la question : How do you calculate a square root? eg the square root of 2.There is obviously some sort of successive approximation type algorithm for doing it to however many decimal places is required, but what is the algorithm? Harley Weston lui répond. 

