# Enumerate list environment split by equation

I need to reproduce the following text:

Basically, I have an enumerate list starting (1.), then an equation environment than some text related to the previously ended point 1. and then after the other enumerated list.

Normally, I would have typed the following code

\documentclass[12pt, a4widepaper]{article}

\usepackage{enumerate}
\usepackage{enumitem}

\begin{document}
\begin{enumerate}
\item Suppose that Susan ... She sets up th regression model:
\end{enumerate}
\begin{equation*}
Y_i = \beta_0+ \beta_i X_i + u_i
\end{equation*}
% TEXT MISSING RELATED TO ITEM ENDED BEFORE EQUATION
\begin{enumerate}
\item Suppose you are interested ...
\end{enumerate}

\end{document}


By doing so the "TEXT MISSING RELATED TO ITEM ENDED BEFORE EQUATION" will be no more considered as part of the \enumerate environment.

Additional ending note: Using this code, the equation environment produces white space above and below the equation stated. Is there a way to better present an equation between two paragraphs as in this case?

• why is it necessary to end the enumerate and restart it? adding \usepackage{amsmath} in the preamble, and commenting out the "broken" enumerate commands, this ran and produced reasonable (if spacy) output. but the spaces can be controlled. (i have to leave now, but there are other people here who can take this on.) – barbara beeton Sep 27 '16 at 21:50
• Sure! Don't know why I started breaking the enumerate environment. – Francesco Bianchi Sep 27 '16 at 22:17

Just type the equations inside the enumerate; there's no reason for ending it.

If you feel that the spacing around the equations should be reduced in this case, you can use enumitem features, but I don't think you should.

\documentclass{article}
\usepackage{amsmath}
\usepackage{enumitem}

\DeclareMathOperator{\Var}{Var}
\setlist[enumerate]{
before=\setlength{\abovedisplayskip}{.5\abovedisplayskip}%
\setlength{\belowdisplayskip}{\belowdisplayshortskip},
}

\begin{document}

\begin{enumerate}
\item Suppose that Susan is a research analyst working for an insurance
company. She wants to analyze whether the color of a car has a significant
effect on the probability of its causing an accident. She has a data set
for the probability of causing an accident (obtained from other data sources)
(denoted by~$Y$) and the dummy variable~$X$ which takes the value~$1$ if the
car's color is red and $0$~otherwise. The observations $\{(X_i,Y_i)\}_{i=1}^n$
are i.i.d.\@ and $n=100$. She sets up the regression model:
\begin{equation*}
Y_i = \beta_0+ \beta_i X_i + u_i
\end{equation*}
and assumes that $\Var(X_1)>0$ and $E[u_i\mid X_i]=0$. Susan's regression
estimate of $\beta_1$ has turned out to be $0.15$. Provide a verbal
interpretation of this result.

\item Suppose you are interested in estimating the effect of hours spent in
an SAT preparation course ($\mathit{hours}$) on SAT score ($\mathit{sat}$).
The population is high school seniors for a particular year. Write the
population regression model as
\begin{equation*}
\mathit{sat}=\beta_0+\beta_1\mathit{hours}+u.
\end{equation*}
List at least two factors contained in~$u$. Are these likely to have a
negative or positive correlation with $\mathit{hours}$? Analyze the sign
of the bias of the OLS estimator of $\beta_1$ in the presence of these
omitted factors.
\end{enumerate}

\end{document}


A few points to note:

1. there is no a4widepaper option
2. either load enumerate or enumitem, not both; the latter is preferable
3. I fixed some of the weaknesses in the given example