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Many of my statistics students will calculate the standard deviation for a set of data using the formula when it is not required or appropriate. When faced with something like $\sqrt{56}$ they will just leave it that way, even for word problems where an approximation is ideal.

They have calculators, but they do not know how to use them beyond the four basic operations.

Is it a good strategy to simply try to overwhelm them with numbers to force them to stop calculating these things by hand and learn some of the functions?

I do not have much class time to teach how to use the calculator although I have explained most of the basic functions. Perhaps they need this in written form?

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    $\begingroup$ How are they to know when it is required or appropriate? Is this not part of what should be taught in the course? Gerhard "Perhaps Got The Level Wrong?" Paseman, 2015.04.19 $\endgroup$ – Gerhard Paseman Apr 19 '15 at 23:49
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    $\begingroup$ How are you sure that they don't know how to use calculators? Maybe they just like to leave things unapproximated? $\endgroup$ – user89 Apr 20 '15 at 4:37
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    $\begingroup$ Try altering the data so that you get $\sqrt{56.123}$ as the precise answer. Getting $\sqrt{56}$ looks way too much like it has special meaning. $\endgroup$ – Adam Apr 20 '15 at 4:56
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    $\begingroup$ Yes, doing the calculation by hand is a nice exercise, but I think it kills the subject if one must fill half a page with calculations over and over that's not the main idea of statistics. I might ask them to compare the coefficient of variation of a few data sets, a simple task that becomes and odious errand if you have to do all the standard deviations by hand. $\endgroup$ – futurebird Apr 20 '15 at 12:34
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    $\begingroup$ Have you told them they are expected to produce decimal approximation? In a very large part of math they are specifically told not to approximate (I would consistently require precise answers as opposed to decimals in analysis and algebra) for reasons having to do with comparison difficulties and the fact we don't teach error bounding. Just because you calculate to 2 decimal points doesn't mean your answer is accurate to 2 decimal points. $\endgroup$ – DRF Mar 31 '17 at 11:48
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Here are two ideas. See what you think.

Find a tutorial (by googling) that gives them some specific tasks, and walks them through doing them, step by step, and assign it. (In future, assign it early in the semester.) You could call it a lab assignment, and ask them to write something up.

Ask them to form small study groups and meet outside class to figure out together how to use their calculators. Then, on a Friday, hold a special calculation race, with a couple of little prizes. Ask for volunteers to bring popcorn to share. Make it fun. No one is too old for fun.

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The answer might be simpler than this. For whatever reason, their prior teachers may have required them the produce "exact" answers, leaving pi or square roots. I'm not going to contradict student's current teachers if that's what they want, but I do remind them that stuff isn't measured that way. You buy things by the lb, ft, ton, etc, and these measurements are to a nearest decimal, 7.48 instead of the square root of 56.

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Make a list of skills you think they lack and combine each skill with a topic you normally teach. Suggest the proper way to the use calculator when explaining the topic. In the beginning of the next class, give a short (2-3 min) assignment for the topic (1, or 2 questions). Make the task favor the use of calculator skill you wish them to learn. This way you can quickly assess their level of understanding both - the topic and the calculator. If needed - walk them through the correct solution inclusive the appropriate use of calculator. Repeat often.

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