S.ID.4

[JRoderique]

Will students be expected to calculate z-scores prior to using a calculator or table to find the probabilities?

[SteveG]

My short answer (at least how we’ve interpreted it in our district here in Florida) is no.
Our district is thinking that students will need to be able to read a z-score table. For right now, we’re going to try starting the unit with just working on the percentages for 1, 2, and 3 standard deviations from the mean, i.e. knowing the 68%/95%/99.7% rule. You can still do a lot with just those numbers.
Then, for the last part of the standard with other areas under the curve, we thought that made more sense to do once students have worked with the easier percentages first. Although we teach students to use a graphing calc to find the percentages, the syntax can sometimes be tricky. So we thought a z-score table was the way to go. At this point, students will calculate the standardized z-score and then look it up in a table.
That’s what we’re going to try. Hope that helps.

[Bill McCallum]

I think you meant “will not need to be able to read a z-score table” in the first paragraph, right? Your approach sounds reasonable, although I could also imagine an approach that does not mention the term “z-scores”. There are lots of possible approaches here.

[Author]

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