A Biology Professor Claims That, on the Average $15 \%$ Of Her Students Get a Grade of A

question 62

Essay

A biology professor claims that, on the average, $15 \%$ of her students get a grade of A, $25 \%$ get a B, $40 \%$ get a C, $15 \%$ get a D, and $5 \%$ get an F. The grades of a random sample of 115 students were recorded. The following table presents the re
$\begin{array}{c|lllll}\text { Grade } & 1 & 2 & 3 & 4 & 5 \\\hline \text { Observed } & 28 & 24 & 39 & 17 & 7\end{array}$

i). Compute the expected frequencies.
ii). What is the value of $\chi ^ { 2 }$ ?
iii). How many degrees of freedom are there?
iv). Test the hypothesis that the grades follow the distribution claimed by the profi Use the $\alpha = 0.01$ level of significance.

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Definitions:

Togaviruses

A family of viruses that includes both the alphaviruses and rubiviruses, which can cause diseases in humans and animals.

Nucleic Acid

A complex organic substance present in living cells, especially DNA or RNA, whose molecules consist of many nucleotides linked in a long chain.

Enveloped Viruses

Enveloped viruses are viruses that have a lipid bilayer membrane derived from the host cell membrane surrounding their capsid, aiding in infection processes.

Stanley Prusiner

Stanley Prusiner is a scientist known for his discovery of prions, a type of infectious agent composed of protein material that can replicate without containing nucleic acids.