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This quiz was administered in-person. It was closed-book and
closed-note; students **were not** allowed to use the DSC
10 Reference Sheet. Students had **20 minutes** to work on
the quiz.

This quiz covered Lectures 13-17 of the Winter 2024 offering
of DSC 10.

Suppose we’ve imported the `scipy`

module. To the nearest
0.5, what does the following expression evaluate to?

`scipy.stats.norm.cdf(-2) * 100`

**Answer:** `2.5`

The average score on this problem was 57%.

Select all the true statements below.

The average of the deviations from the mean is a meaningful measure of the spread of the data.

It is possible for the standard deviation of a dataset to equal zero.

It is possible for the standard deviation of a dataset to be negative.

Given the standard deviation of a dataset, we can determine its mean.

Given the standard deviation of a dataset, we can determine its variance.

**Answer:** Option 2 and Option 5

The average score on this problem was 80%.

The Oscars, or Academy Awards, are the highest awards in the film
industry, awarded each year to the best movies of that year. The
`oscars`

DataFrame contains a row for each movie that has
ever been nominated for an Oscar. The `"name"`

column
contains the name of the movie and the `"rating"`

column
contains a rating of the movie on a 0 to 100 scale. This number
incorporates many factors, but we won’t worry about how it is
computed.

Fill in the blanks below to collect a **simple random
sample** of 400 movies from the `oscars`

DataFrame,
then calculate 10,000 bootstrapped sample mean ratings.

```
my_sample = __(x)__
n_resamples = 10000
boot_means = np.array([])
for i in np.arange(n_resamples):
resample = __(y)__
mean = __(z)__
boot_means = np.append(boot_means, mean)
```

**Answer (x):** `oscars.sample(400)`

The average score on this problem was 85%.

**Answer (y):**
`my_sample.sample(400, replace=True)`

The average score on this problem was 87%.

**Answer (z):**
`resample.get("rating").mean()`

The average score on this problem was 96%.

In each blank, circle the word that correctly fills in the
sentence.

*A histogram of boot_means shows a(n)
probability / empirical distribution
of a statistic / parameter.*

**Answer:** empirical, statistic

The average score on this problem was 77%.

Suppose we use the array `boot_means`

to calculate a 90%
confidence interval for the mean rating of Oscar-nominated movies.
**Select all** correct conclusions we can draw about this
interval.

There is a 90% chance that the true mean rating of all Oscar-nominated movies falls within this interval.

The sample mean rating is within 90% of the true mean rating of all Oscar-nominated movies.

If we looked at the ratings of many Oscar-nominated movies, about 90% of them would fall within this range.

None of the above.

**Answer:** None of the above.

The average score on this problem was 74%.

Suppose both of the following expressions evaluate to
`True`

.

`my_sample.get("rating").mean() == 61.25`

`np.std(my_sample.get("rating")) == 15`

What are the left and right endpoints of a 95% CLT-based confidence interval for the mean rating of Oscar-nominated movies?

**Answer:** left endpoint: 59.75, right endpoint:
62.75

The average score on this problem was 54%.