Confidence Intervals: Crash Course Statistics #20

Today we’re going to talk about confidence intervals. Confidence intervals allow us to quantify our uncertainty, by allowing us to define a range of values for our predictions and assigning a likelihood that something falls within that range. And confidence intervals come up a lot like when you get delivery windows for packages, during elections when pollsters cite margin of errors, and we use them instinctively in everyday decisions. But confidence intervals also demonstrate the tradeoff of accuracy for precision - the greater our confidence, usually the less useful our range.

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[EChu]

I'm 95% confident that students like us cannot retain information verbally

[svwtsvfcb]

I have my statistics exam in 2 days and believe me, I'm not 95% confident of succeeding at all

[Tawkitoutti]

started off okay and just devolved into noise where i would occasionally hear 'distribution'

[nasia]

Crash course should have the math written down or drawn out instead of just telling us the process of the math. It's hard for me to imagine the math in my head. The graphs help though!

[waterfairy]

4:10 calculate 95% CI
7:00 t distribution
to calculate t distribution, use program
10:40 margin of error

[gingeraira]

i am 95% more confused than I was before

[jakeborrelli]

im 95% sure I'm gonna fail my exam tomorrow ahahaha kms

[Mgaby]

i have a stats exam in 3 days and you taught me more in one video than my professor has taught me in two weeks. He didn’t even teach us about confidence intervals but put it in our homework. So i thank you so so much for this, but i still think i’m gonna fail my exam.

[victornoagbodji]

ah stats... always very intuitive at the beginning. and then becomes less and less intuitive. it's just new terms and formula at some point. there is no "big picture" to help you find where you are or why you are there. anyways, great explanation as always.

[briaryos]

Confidence interval formula is : the mean, plus or minus (standard deviation / sqrt(sample size)) * the Z statistic.

The Z statistic in this example 1.96 because of the desired 95% confidence interval. If it was exactly 2 then your confidence would be 95.45%. If it were 3 you'd have 99.73% confidence. So basically, the wider the range (or the greater your sample size), the great your confidence. The narrower your range (or the smaller your sample size), the less confidence you have in the accuracy of the mean.

[d_wang]

Confidence and Stastics are words that people usually wouldnt put in the same sentence

[orangeflip]

Should have added more graphics to this episode. It's hard to follow along

[awaisafridiyt]

statistics lesson on crash course should be more like written rather than oral explanation.

[francoislacombe]

I am 95% confident there won't be gold lame pants next week.

[wafelsen]

In a paper almost certainly prepared for a statistics class, someone found the mean length of 30 randomly selected top 100 songs from iTunes was 226.93 seconds. Seventy songs of that length will last you through a 4 hour 24 minute marathon.

[Satyamsingh-dory]

i understood every lect in this series before this lect.When the t- dist started, it got too complex.

[grumly]

I’d have to buy the whole music store to finish my marathon. Which consequently would make me sure to finish it. Nice trick!

[blahblahblahox]

I agree with everyone's complaints that they don't show the math - but does anyone know a good alternative that does show it step by step? Would love to know!

[ishykiller]

The fact there is no examples that explain exactly how to find a confidence interval is a crash course is crazy. Just explaining terminology isn't enough SHOW US HOW.

[PurpleBaconEater]

glad I'm not the only one more confused after watching this video than before. stats its the only time where crash course has failed me.