Hi there

There are no dumb questions Newton!

First thing to do is identify the type of distribution that suits this situation. Two possible answers (it lands logo up or logo down), there are a fixed number of trials (it was spun 20 times and the position of the logo was noted), each trial is independent (how it lands each time has no impact on how it will land another time) and the same chance of a success (presume that there is a half chance of it landing each way). This leads us to Binomial distribution. Make sure you justify this by going through each condition.

Next look at the specific case. We are wondering if getting 13 is likely due to random variability or not. We look at 13 or more landing facing up to see if that â€śtailâ€ť of possible results is likely with a probability value of 0.5. If 13 or more has a really small probability of occurring, based on sampling variability, then there is evidence to suggest that 13 times of landing logo up is unlikely to be a random event and more likely attributed to an unbalanced racket. In this case, with a probability of 0.1316 (or 13.16%), this isnâ€™t particularly small and therefore it is likely that this number of times that the racket landed logo up could be attributed to random variability rather than unbalanced rackets. This is also backed up by having a small number of trials (only 20) and therefore it is actually very unlikely to get exactly half of the spins for the racket to land logo side up. Remember that random variability means that every time you run an experiment or take a sample, you will get different results.

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